Andylynn said:
late answer but after poking around people seem to believe that the higher your wyvern's hp the better % your next hit has a chance of hitting. though the only sample is one 1 on one beetle on wiki, he recieved ~100% increased damage hit @ 100% hp wyvern. I.E. current theory, keep your wyvern @ 100% hp for a chance @ double damage.
Pretty much.
It seems like you get increased chance of increased damage for each piece after the 2nd. Damage is based on wyvern's hp %, not his overall HP. In my experience: It does work on jumps, however, it does not work with WS (eyeballing but my experience would match the results of other af3 added effects).