Can't you just use moveto to put your pet in front of the boss on the platform where you spawn adds? Sure it may get parried on boss damage occasionally, but then he barely has to run anywhere for the BC damage, which is where the padding for Immerseus ranks comes in. That's what I've done any time we've not had someone specifically padding for ranks.
I've tried the master call thing but it seems to just sit there and run normally. Doesn't work very often.
I tried the "move to" option last night and it still blinked to the back when I sent it to attack. I ended up just letting it sit by my side the whole time and realizing ranking Immerseus just isn't for me on hunter.