The C152 fleet in the Uk had a performance write down issued by the CAA some 10 years back. This took into account that the fleet was getting on in life.
The POH for a C152 states 'MAXIMUM' on the climb performance table page. So that'll be a factory fresh aircraft, company pilot and perfect weather conditions. Equalling (or even getting within the 70fpm shortfall allowed on a CofA air test) 'maximum' climb figures on a 5000 hr airframe and half life engine and prop was always going to be a tricky mission.
Not quite the same case as with the SportCruiser me thinks.