FlashJump for Slingers

If that's maxed, why do I go faster? o.O

Do you use the macro skill like the video posted above?

For me, I don't use Macro Skills and I don't have any speed equipment, but
I can do the float thing way much faster just like you said.

I think it is because of the timing between Recoil Shot and Float.
If you get the timing just right, you can float a lot faster than the video posted above.