Easy way to test it. Get a SMN and a BST. Use Predator Claws on a DC-EM mob (so it can survive it) then have the BST immediately charm it and use the <pettp> command. If you timed it right and the mob didn't get to hit anybody/didn't get hit by the Avatar, then the mob should have either 0TP, or 30TP.
I've always been told that BPs give TP equal to X * 10, where X is the number of hits of said BP. I think the reason you didn't see Cactrot use any TP moves is that most mobs whose HP is >25% hold TP till 300TP (or maybe it was random), and then when they get to <25%, they use their moves at 100TP instead, and so it would take 10 Predator Claws for it to reach 300TP, and it may very well be dead by then depending on what other damage is being put on it.
The other, and more likely possibility is that it used one of it's more useless TP moves and you just happened to miss it, whether due to log box spamming, gear changing, or filters.
XI Wiki

BG Wiki no info, Banned Wiki says 24-36. Friend seems to think 3 days after death on dot.
