“All-mix” is not a protected term.
Anyone can put whatever they want in there.
And you’re supposed to buy the CalMg too 

So, I would follow @BunkerAriel’s lead on that.
Dolomite lime is an all-rounder.
If it’s too acidic, it buffers it up until, after a certain degree of acidity, pH level, the reaction automatically subsides, because
calcium and magnesium carbonate react with acid, so once the environment is in an acceptable range, the activity decreases.
I mix it in at every opportunity, right into the soil before the grow.
But sprinkling it on top, working it in, and watering it in—without drain at first—I think works well too. 
Cheers 
Edit:
Just checked the manufacturer’s website. It doesn’t say anything about it already being limed. A combination of highly potent slow-release fertilizers is supposed to be in there, though. You’re supposed to feed as needed. But I actually understand it as having been invented as a living soil experiment.
That wouldn’t have been my personal first choice. But it is what it is now.

Dolomite