Can't get Reainsert to work.

[Tubeguy]

For the life of me I can't get Reainsert to work. When I engage it, I get even more latency than without it, it's actually more of a delay.
I put it on track I want to send to FX, set the send and receive in the window, than record the returned FX to another track. But when I play both tracks (to mix them), the recorded one has huge latency. Anyone came across this problem? I must be doing something wrong.