Wayne --
After we got permitted for my shop and driveway and the plans all signed off on --- THEY found the "bridal trail" on my property... and so it was an all stop - and re-do. The surveyor guys use GPS and my shed is less than ONE INCH from that bridal trail! They assured me they could get within about a quarter inch.
Of course 10 years from now -- we'll sell -- and they'll have new fangled equipment which is more accurate - and they'll tell me the shed in 1/2" into the bridal trail! LOL
These things can cause you to pull your hair out - shorten your lifespan - and put bags under your eyes... IF you let it.... so don't let it get to you -- it'll be fine -- they're NEVER on time - things go sideways... it's how you deal with it that counts. In the end -- it will be GREAT.