I'm not an expert so sorry if things I say are not correct, but...
They seems to be different sails with totally different shapes so this could be the reason. Note that my old Gaastra GTR 6,5 from Barry Spanier has 463 mast and 203 or 205 boom, my newer HSM Speed Demon 6,5 has SAME mast lenght and 193-195 boom. Both 7 battens nocam, imho no relevant difference in power (but meanwhile I changed board), only SD is more direct but also more easy to rig over the FS 4600 (suggested GTR mast...).
Looking at both sails pheraphs Pursuit is a FR-FC nocam (like all my big sail, so less prone to be used owerpowered, but I suppose with more low end. Ezzy has his classic exposed head and comes from the ten years old classic shape of all ezzy wave sails.
But yes, some obiectivity would be appreciated, none is checking as I know the real sail dimension when testing, could it be with an engineer device? I don't know.
But the thing I could be mostly interested is about the REAL weight of a board, so pricy and you don't know if the specs are about a fully naked board (without pads - absurd), or with pads straps and fin (abdusrd on the other side, imho fin is underwater so weight changes a lot). There isn't a common rule. Finally a wet-straps test could be useful, as some board has heavy 4 sponges... Some tests show big differences from declared to real weights.