User blog comment:Mich, Michele & Kuhla/Future Units Preview/@comment-26940790-20160216232359/@comment-26944381-20160217032947

2 things:

1st - I was speaking about the UBB, not the BB/SBB (I forgot that those had parameter boost jeje).

2nd - Mich is right, the "all parameter" buff doesn't apply to the HP, you can see that by using any unit that has the "boost all parameters" buff on it's BB/SBB/UBB, using it you'll see that the HP doesn't raise.