You are correct.
FFP reticles can be a disadvantage for precision shooting at long range for the exact reason you mentioned.
The real advantage to FFP scopes is that the subtensions are accurate at any magnification setting. So, if you need to range with your reticle, for either hunting or target applications, this can be beneficial.
If you shoot target at known (long) ranges, an FFP scope is a disadvantage. It's common sense that a more precise poa can be established with a smaller reticle on the target.
Vortex has a good video explaining the difference: