I think this stuff need a little more testing, playing around with it today for the first time, I was getting very mixed results whilst fighting an NM.
Pet: Dipper Yuly
Lv90 HP: 4078 (Accourding to wiki)
Mulsum 1 = 1602 HP recovered (39%)
Mulsum 2 = 1938 HP recovered (47%)
Mulsum 3 = 1310 HP recovered (32%)
Obviously not the biggest test sample, but it shows that the previously reported 30-35% HP recovered isnt quite accurate.