Each chain treatment uses only 3-4g (0.14oz) of wax if you let it drip back into the crockpot while it dries. We actually weighed it. If you clean your chain with boiling water (see video below), let it dry and then wax, you could get around 62 treatments and still have 100g (3.5oz) left in the pot to guarantee full immersion of the chain. It's only a matter of how much you contaminate the wax or how good you clean the chain with boiling water prior to every waxing. Wax will still last the same number of applications regardless of cleaning, but if you contaminate the wax too much, it will no longer be as effective.
It's like walking in the house with shoes on. The floor is clean as long as you clean your shoes every time you enter the house.