That was my understanding as well. I'm not too privy to the details of how many sen should be hagakure'd though.
It was my understanding that sen are always better used with hagakure (provided no party buffs). Which in theory means that hagakure on 3 sen is better than hagakure on 1-2 sen. The question I have and would love an answer to is: How long is too long to be sitting on hagakure while waiting to build up 3 sen? There has to be a point where getting the CD back earlier outweighs the benefit of using it on 3 sen?

With that said there are a number of party buffs / combination of party buffs where you will prefer midare. Things like trick attack etc.. I'm sure someone more competent can chime in.