Haha, sorry about Plunge!

And yeah, I guess I should mark that as "I am not a great DRK" since I delay my Scourge there so I can mix it with Plunge (30s cd / 30s dot) without using Plunge during Grit. It's my own shit thing I do.

The reason I do one PS > drop Grit is because that's how I have been playing PLD and it works beautifully. It's more organic on PLD and a bit icky on DRK, though, but that's neither here nor there. Either way, you shouldn't need to turn Grit back on to grab hate back - just use another Power Slash. I tend to use a bunch early on after that initial DA+SE (since mana needs to drop!) and it generally balances out nicely. If you're evenly geared with the dps, you shouldn't need more than 1 Grit PS to hold hate, honestly.

I also ran numbers before - each cast of Blood Weapon (15s - 7 gcds + 6 autos = 13 shots = 3.25 Syphon Strikes) accounts for three Power Slashes in terms of mana regeneration, so meh. It's about half as effective, but also keep in mind that you don't need all the DPS to be 50% or below to hold hate. They can be 70-80% and you've still got a huge lead.