ashewyntr's page

Aid grants the target a +1 morale bonus on attack rolls and saves against fear effects, plus temporary hit points equal to 1d8 + caster level (to a maximum of 1d8+10 temporary hit points at caster level 10th).

The max you can get from Aid is 18. Specifically stated in the spell. False Life is good for 20. I don't see why spells with no stated limit don't stack, but those that do have a stated limit can't exceed it.

The RAW don't specify anything about stacking either. It merely states the ability lasts a number of rounds.
In theory, I could spend 1 KI, gain Smoke Bombs, spend another Ki, get Poison Bombs, and then spend a Third Ki to get Choking Bombs. So 3 Ki in one round to get a third tier Trick.
I've been toying with gaining Bleeding Attack in the first round, then adding Flurry of Stars so I can bleed a crowd.
Unless the idea is to burn through Ki rapidly, this should probably be clarified.