The rating 70/F/A/W/T should be enough to carry any civil aircraft.
The highest ACN civil aircraft in the world is the A340-600 @ 381t: ACN on A subgrade flexible is 66 (Airbus say 70 but I am having some difficulty matching their numbers), followed closely by the Boeing 777-300ER @ 352t: ACN on A subgrade flexible is 64.
Hint - COMFAA 3.0 has a little trick to it for airport engineers – the library A340 models only go up to the -300 and so when you have to derive the -600 from first principles, the % main gear gets set to represent only the wing gear at 63.5%, and ignores the 110 tonnes load on the centre main gear.
The reclassification of pavement strength occurs periodically at airports following a technical evaluation without any construction work necessarily being associated with it. Technical evaluations should happen periodically (ranging from 3-10 years), and are typically done with non-destructive FWD testing of the pavements. They may or may not be done in conjunction with some construction work. Often an airport may get engineers in to design and rehabilitate some piece of pavement which requires them to bring in testing equipment before the design, and as an inexpensive extension to the work, some other pavements will get tested.
Because some airports can have many sections of pavement – presenting different sections along the runway(s), and the various taxiways and aprons – the testing may be limited to key areas only. I have seen international airports with over 100 pavement sections – each managed individually – and I am sure there are airports with many more than that.
I have just done one such technical exercise for an international airport, and this resulted in reclassifying the airport pavement strength upwards.
The normal process in such technical analysis is to estimate the subgrade strength using various techniques, and then strength of the pavement layers, and finally the PCN. The decision rigid/flexible would come from consideration of the layer depths, the concrete (rigid) condition, and the data from the FWD test back-calculation; such a decision would require a couple of days of analysis.
It is not possible to draw any inference about the PCN of other pavements, such as 06/24, from this analysis. These are very high loads at these sort of PCNs and extrapolation is unwise.