Tile might be the culprit here. Viewing the slab horizontally wouldn't really change much in the colors. It's more about the lighting. Anyway, back to the tile. So, there's a big chance that the tile is NOT from the same quarry as the slabs. And even if it is, it's definitely not from the same batch of stone. Quarries use inferior blocks of rock to cut tiles (because unlike slabs where imperfections are hard to avoid, tiles are cut smaller and thus can use more of the "good" parts of the block). If you're still in doubt, go back to see the slabs.

If you can, go back to the slab place to take more pictures.
I took horizontal and vertical pictures to help me imagine
the slab flat on a counter.

I remember this beautiful Sapphire Blue Pearl granite that
looked more taupe/brown than blue. And my DH and I walked
around and found another Blue Sapphire Peal that was Royal
blue. Totally different! We asked and were told they were
from different batchs.

I am sure the tile that your KD showed is not the granite
you are using in your kitchen. But of course run and take
more pictures so you have a good idea of what you will
have.

One very useful piece of advice I got from all the trips to granite places was to select a backsplash after your granite is already installed in your home. That way you can see the way the backsplash would look in YOUR house with YOUR lighting. It is possible that the tile you saw was cut from the same lot but very possible it was a generic sample. The same stone can look different in different lighting. I loved a piece of madura gold in the stone yard which looked very creamy and tan (I took photos of it which showed this too) but when I took home a sample it showed as much more orange and peach - I would have thought it was a different lot, but it wasn't.

We viewed our slab outside, and we liked it, once it was installed the colors were richer and deeper, which we loved..lighting makes a big difference.

Go back to see your slab and take the KD's sample with you. I'd wait until it was installed too but you could be like me, undecided now for over a year.

Oh, wow, I can certainly understand the stomach flip flops. I hope it's resolved without further aggravation. natesgramma's tip is a great one.

I've worried about this same thing, especially because my aging eyes aren't as sharp as they used to be.

A friend and I went to a granite installation company yesterday just for a look-see. Boy, does lighting ever make a difference. Even though it was all indoors with the same overhead lighting, where the slab was in relation to the lighting made some easy to view and others pretty darn difficult, especially the darker granites.

I want to make sure that it's not bad lighting that causes me to pick the wrong granite. Anybody have any lighting tricks to get a better look at granite slabs? I could take a flashlight but that would give me lots of glare. TIA