Got out on my road bike yesterday for the second time in the past two months or so. The saddle felt strangely high. I noticed it a couple weeks ago, but yesterday, I actually remembered to check the measurements. Turns out it was about 3cm higher than my trainer bike. Went back to my fit files, and sure enough the road bike was correct. The trainer bike saddle has been slowly slipping, but because I spend so little time out on the road, I didn't notice.
3cm is a big difference too.