Curious. I just double checked, and my bless skill says that it Boosts stats by 3 for 15 time units, (lvl 1). Seems a reversal of what you suggest, and also a reversal of all of the online skilldexes I've checked. Unfortunately my printed manual has no figures at all.

Is this a sign that the skilldexes are all out of date, or that my patch didn't work properly? (I'm running ver. 1.0034a, the latest North American patch).