At a 2.5s GCD, you have the option of reapplying GB's DoT 1.5 seconds early or 1 second late (SS once). [Take your pick.]
At a 2.4s GCD you have the option of replacing it 2.4 seconds early, or 0 seconds late (SS once). [Pick is obvious.]
I'll admit, I've got a lot more SS than I want right now, but for me Swiping once per GB is a definite dps increase.
