Don't get so obsessed that one aspect of a fit must be maintained and sacrifice the other aspects that may actually be more important for your particular body.
Rules for the various fits are just guidelines to get you in the starting place to begin adjustments to find what works for you. IMO of course.
As well, when you talk of fit... are you wanting to be fitted for ultimate comfort? Best performance on a long ride? Best speed on a short ride? or some other aspect?