Hmm i was not getting anywhere near those numbers with 5/5 merits, but I was sub war with atk food, agressor up, and berserk up. Atk was 999 on ws.

Averaging 700-900 on TW mobs with 100 tp using a dex build for ws swap. (+68 dex / 45 str on ws)

Only time i saw it break 1k dmg was with 300 tp. I guess I could try in abyssea and see what kinda max numbers I could get but I was not very impressed with the dmg on too weak mobs.