It was determined...how? I'm not trying to pick on you, just pointing out that Cervelos - and namely the P3 - have had significant geometric changes over the years. Other bikes have had smaller degrees of change, but the P3 is probably the most iconic bike Cervelo has made.

The old P3 had a frame geometry of 498 mm (stack) / 419 mm (reach) in a size 54. The new P3 is a 522 mm (stack) / 411 mm (reach). The new P3 is an inch taller than the old P3 in the same size.

It's folly to say "I'm a 54" or "Cervelo fits me well". It's more appropriate to say "I'm a 54 on <whatever bike>" or "Cervelo <new P3> fits me well".

And it should be noted that frame geometry is now an inferior way to identify your best size - your fit coordinates are where you touch the bike, and the future is using armpad geometry to determine what bikes/configurations are appropriate and ignoring frame geometry altogether.

All of that said, I'm glad you're happy with your purchases and, no doubt, Cervelo makes excellent bikes.