If using platform pedals and soft soled shoes, the variation those two introduce into the equation more or less negates the precission of a retul or similiar fit. However, there's no reason why a "good" standard, professional fit shouldn't be able to address any back or knee issues that can be addressed through the fitting process.

Sometimes the solution is not the fit but the athlete. I witnessed a retul fit for a national level age grouper that resulted in some changes, but, more importantly the advice that the athlete go work on core strength and flexibility exercises then return.