How does placing bloodletter on a heavy/straight shot, "reduce" DPS? If you're not using that every time it is up you're wrong.

/macroicon "Heavy Shot"
/ac "Heavy Shot" <t>
/ac "Bloodletter" <t>

You can spam the macro and get bloodletter off anytime it is up.

I don't recommend macroing buffs, but Bloodletter shouldn't be used if your GCD is up. Also, with how often it procs and the no TP cost, you should be using it anytime it is up between GCDs buffs or not. I can't see how this would reduce your DPS.