I posted this on the building a home forum, but figured people here are probably full of good advice too. I'm building a garage apartment and in a few years will build on the main portion of the house. I have rough plans for the main house, but basically it'll be connected on the east side and extend out. I originally planned to just design everything from scratch, but found a plan that was pretty close to what I wanted, I just modified a few things. Does anyone have experience modifying online plans and if so, is this too much (as in the site will just say I need to go with a new plan anyways)?

Original plan - http://www.coolhouseplans.com/details.html?pid=chp-25094&FoundID=1&sid=chp1

And here's my rough modification.