We had a design consultant who works for Ikea's Installation subcontractor come out. She did the measurements, but our GC was on site and helping.
With their collective expertise we got:
1. Our range listed as 40" when it is 48". That was the designers fault. I caught that one right away and we did some quick reconfiguration that fixed that issue.
2. A kitchen that is 2" shorter than we expected. I figured out how to remedy it, unfortunately we are going to lose a 15" wide floor to ceiling cabinet in order to correct that problem.
This whole experience has been one terrible frustration after another.
1... numbers. math. difficult.
2... damn- sucks. useful cabinet to lose. I don't know the layout, but there's no way of shrinking something else and keeping that? IIRC, ikea cabs come in 3" increments... you can't swap out one of the others for something 3" less (and then add a 1" filler... yeah, yeah... that's what my wife says... I get it).
really sorry it's not gone more smoothly. only consolation I can offer is that by this time next year, all of this will be a distant blip in your rearview as you're enjoying the house as you had hope to.