Would anyone say a P3 rated driver is just as qualified as P2 or P1 and is totally capable of flying the aircraft and knowing the machine technically....
If you take into account that a certain SAA boy pilot—oops, you're not allowed to call them that anymore—uh ... P3, managed to get a direct entry B744 command at Atlas UK (or GSS, whatever they call themselves these days) a few years ago, with no more than a "P3" qualification, I'd say there's a case for for your P3 bloke being as good as old Kaptein (do they still have to call him that at SAA?), even!