Well done, I am still trying to figure out at what point 6 pets can be controlled if at all, so far results are quite disappointing
Up to 5 pets the extra pet unlocks every 12.5 levels (as can be seen in Rob Vee's great chart). However after that nothing happens neither at 12.5 or even at 25 levels above that.
It either means MA just did not implement it, or has managed to set a really crazy trigger.
5 pets unlocks at level 43.75 or so I think, so go go go nln, great progress.