It has to do with the way Tuned calculates how much to enter trade with. If you use equal leverage values it could fail to have enough in available to trade by a few dollars.
Tuned also manages all the leverage liquidation prices automatically on our side. So if you have a 50% 2x bot and 50% 3x bot on the same pair it won't mess average out to like 2.5x as it may appear if looking at exchange values.
Since we don't track some of the smaller, fees like funding fees, you should leave some headroom for the margin. If not, it could fail because the order size gets blocked by the exchange.