Seems to me that a bike fit is not an exact science with only 1 outcome.
Also, there are trade-offs between Comfort and Performance.
What is meant with pro vs amateur fit is that a pro fit is aimed more towards performance than an amateur fit.
But also as an amateur when you get a bike fit, the bike fitter will first sit down with you and discuss what your goals are. So if you indicate you want to go all out for performance you can get a pro fit just as well.