How to use Magic Crash?

Most bosses have a cooldown on casting pdef up. If you can time it (eg. Scarlion's is roughly 60 sec afaik) you can just wait 45-50 seconds after the first time it uses def up and then magic crash a minute later for the rest of the run.

Would be interesting to have these values especially after BB for zak/c-zak/pb.I remember PB's reflect being 20 seconds and then having a min cooldown.