Originally Posted by
Adyssa
Here's an example of what may be occurring when adding 1% haste. Say you have the wait time set to .5 seconds, such that if your main shot is .5 seconds or less from coming off cooldown, it waits and then uses it. If adding 1% haste makes a steady shot or cobra shot end .6 seconds before your main shot, it's no longer going to wait, it's going to start another steady or cobra and then do the main shot after that, thereby pushing the main shot back. If adding the haste causes it to do this a few times in a 5 min fight, then you might end up dropping a main shot off your total and lose some DPS.
Check your shot totals and see what happens when you add the haste. You might see, as MM for example, that you add 2 Steady Shots but lose a Chimera Shot, which would likely lower your DPS.
There are other shot behaviors you can toy with as well, like how much focus you have before using Arcane and how to manage Steady Shots for MM.