Hi,
Have you tried counting number of movements the club makes on backswing? Divide club distance/number of movements= length for each movement of the club.
This allows you to not have to use the meter to estimate 90% or whatever the shot requires.
It could be that when you us the meter to estimate percentage of power you are at the point when the length of backswing changes distances.
It is just like putting, but if you know how far each movement of the backswing is, you can come reasonably close to the distance you want.
Hope this is new info and it helps, if not, sorry. You can read the putting tips and apply the advice to most of your other clubs.
Good luck and have fun, that's what it is all about.
dacrash