Correct, Max DD % is always a percentage of the gross profit of the simulation.

Using a balance peak instead would be not much better than acidburns idea of using an equity peak: Suppose your simulation starts with the first trade winning $10, the second trade losing $20 - a rather normal situation. This would be then a 200% drawdown, regardless if all subsequent trades are won.

Myfxbook is no trading simulator and does not calculate a DD projection at all. It just tells you your current DD. If I'm not mistaken, it also displays the max DD % as a percentage of the profit.