MRDs Path of the Storms + Whirlwind combo: Build TP to 1500 -> use Path of the Storms from behind mob (running through works) -> Buff Blood for Blood (more dmg), Keen Flurry (lower next WS recast) -> use Whirlwind (no TP cost).

Whirlwind has a really long recast (+1 min, can't remember exact value) so to spam it more often you need Keen Flurry from LNC (lvl26). Path of the Storms still has around 30 sec cool down so that's about the fastest you can spam it, as you need it to open combo for Whirlwind. And Storms needs to land from behind or the combo won't start.

When using combo, only the first WS costs TP, recast timers for skills aren't affected in anyway when doing combos. It's just that, to use Whirlwind without combo you need 3000 TP, in a combo you can use it without TP cost after landing Path of the Storms, which only costs 1500 TP. So it's faster to use Whirlwind after Storms rather than build TP for single Whirlwind execution.

Just to clarify.