What is the "plan" exactly and what is the "wish list?"

I found that my architects bid documents and selection schedule resulted in a tight range of bids. Within 5%. There wasn't much room for ambiguity.

"I would love to have wood look tile!" could potentially result in a range from 5k to 55k. Which tile? How much of it? Where?

There was one outlier. Yes, he was busy and didn't really have time for the job, but if I was willing to overpay he would accommodate me.

Using different subs? There's always new guys trying to "buy jobs" that will be cheap, and inversely the "get what you pay for" more expensive subs.
Allowances?
Sometimes they will completely leave out landscaping/appliances/etc so check for missing allowances too

Are these final bid documents or just a plan from the internet?

How specific did you get in terms of the type of moldings you want, door types, window type and brand, roof shingles, flooring options, plumbing options, granite options, kitchen and bath cabinets, low voltage options, number of lights, etc. Did you specify whether or not you want 2 x 4's or 2 x 6's? Did you specify exterior materials? HVAC brand? And basically all the 100's of other minutia that one has to decide?

If not, that is probably why the large difference in pricing.

Thanks for the replies.

I specified the following:

exterior materials, flooring, granite grade, cabinetry, plumbing, moldings, lighting, door sizes, ceilings, fireplace, closet systems, built-ins, outdoor living.

I was general on HVAC - said I wanted 2 units for main/bonus. I was also general on windows-said I wanted all square tops with exterior hardie trim.

I instructed them to leave out appliances and landscaping.

Did you specify whether your plumbing used thermostatic or pressure valves in the showers for example. What about all electrical?

Was the plan a finished bid doc they used with all the framing, concrete etc specified?

I was general on HVAC - said I wanted 2 units for main/bonus. I was also general on windows

Price variations on these two items alone are in the many thousands. For instance, I always installed first-line high-efficiency furnaces whereas tract builders consistently use second-line brands. Outside the trades, you wouldn't know the difference. The price variance between windows is easily triple and quadruple between the cheapest and top of the line. And yet all of them will meet minimum Building Code requirements.

If you want comparable quotes, prepare better bidding documents. You'll also end up with closer to what you want.

Did they provide an itemized bid where you can compare the quotes line by line?

Are all of the contractors offering the same turn-key services?
For example, the contractor my BIL used was WAY less than one of the other contractors he quoted because that contractor allowed him to select some of his own subs and he also did site cleanup and dirt work himself. The other contractor he quoted only did turn-key and would not allow for any DIY.

Cost differential

This may not be the answer to your question, but I imagine folks here will get a kick out of it.

Estimating costs is not the same thing as bids or a contract price. It takes a lot of time and effort for builders to prepare a contract price for a custom home. And materials and labor costs may change daily. Thus, when it comes to estimates, builders may be all over the map in terms of how much time and effort they put into a non-binding estimate. Said differently, estimates are worth exactly what you paid for them. They are nothing more than very rough "guides" as to what the actual construction cost may be.

Good luck on your project.

You need to provide as much detail as you possibly can. This removes doubt and fudge from the builder's bid. They aren't psychic. A good builder who wants your business will take the time to ask detailed questions. Leaving windows, HVAC, plumbing, etc. up the builder to guess will result wide disparities in pricing. There are a thousand decisions that need clarity. Take the time to get educated. You don't need to be an expert, but you do need to know enough to clearly describe to a potential builder your desires. They will help you though a lot of this. If they can't, it doesn't bode well for the finished product.

Being detailed isn't being a PIA, it's the beginning of a good relationship that will put you in the position to become a future satisfied customer.

On second thought, are you using proper terminology?

Are the prices from the five builders competitive BIDS, for which they will sign a construction contract, or...

Are the prices from the five builders simply non-binding ESTIMATES (which is the term you used)?

Big difference in the two terms...

Do all builders have the same exact profit and overhead margin? Have you provided detailed architectural, structural, civil, mechanical plans to each of the builders? Have each of the builders done a systematic take off on all materials used for your home? Have you looked at that and are there variances? Do you have a spec sheet for down to the minuscule detail and finish?

Don't just hire a builder because their price is lower or higher. If the contractor takes several weeks to get back with a very detailed bid, it is in fact a good sign. The devil is in the details.

Estimating can be hard. There are always surprises. Plan on a 10-15% contingency fund that you can tap in, other than P & OH for the builder.

I wish I could give Virgil Carter's Fine Art comments 100 likes.

Estimates are very different from binding competitive bids. Estimates with the range of prices you indicated are either based on very preliminary plans/specs or nobody wants to put the considerable time and effort required to produce a true competitive bid. With five bidders the probability is only 20% of being the "winning" bid.

As one person replied, competitive bids for a thoroughly documented project (architect quality plans and specs) would be expected to fall within a +/- 5% range. In my experience, the incremental cost to produce design documents to that level of detail is less than or equal to the cost saved due to competitive bids.

Are you getting the cheap $79 vinyl window in one estimate? Or the $560 one that is the right color and energy factor and that will save you money long term? Are you getting the cheapest 13 SEER single speed HVAC allowable under code in that cheap bid? Probably, because it seems that the actually important details that aren't flashy aren't important.

You are willingly getting on that upgrade merry go round because you haven't done the proper design documentation on the front end. You have no standard document to even compare estimates. The estimates that you are getting are completely worthless in determining an actual end price of constructed home that will perform well and be a place to shelter your family.

Shiny granite and cheap import hardwood isn't what it's all about. But it seems that surface gloss is all you care about. If that's not accurate, then you have a lot more work ahead of you to research all of the truly meaningful details. Or, just hire an architect who has already been educated in everything that you would need to learn. Then have him design and specify something worth owning.

Or just go buy an existing home. It will be cheaper in the end and you would be getting a fairly known end result.

Is the OP still in the building? These comments are all over the map, and no one truly understands what the OP is asking, since the terminology and interpretations make all the difference.