Minion revive speed

I play a minion explody build and minon revive xx% faster is important. I have heavaly invested in revive speed in my tree but no noticable effect appears. There is 2 issues:

-Let's say, I have minions revive 100% faster (I have a more than that). My expectation was to halfen the time of the revive. It is not the case, at a point I feel it does not work at all. With this investment i still wait 4-5 sec for revive to occur.

-If I have multiple persistant minions, if one die while minions are reviving, the reviving time is reset. So sometimes, you might not revive your minions if they die with the perfect timing (until all are dead of course).

I did the same and thought I was going mad.

I have similar experience, I don't think the formula for revive speed works correctly.