@bbmess I have to constants which show up as input in the EA. One is RiskPerTrade, the other is the SL. They can be simple variables, maybe calculated, that depends on the strategy. But I would do this in a separate tree, leaving the formula tree only to calculate lot size. The formula is simple so it shouldn't give errors. (Desired risk percentage * Balance) / 100, or.... (desired risk percentage / 100) * Balance. This amount is then divided by SL = LotSize. I hope this formula in itself is correct, but I see you tried the same with the parentheses, and this is what I found on the web when I did this.
I suspect that this SL amount is what is making the problems... because of broker's decimals, as you said in a previous comment. 100 pips on EUR/USD is something, and on the indices is something different, and maybe that's why you get maximum lotsize possible. So it's necessary first to establish correct SL, and you can do this in a different formula blocks tree, then get the SL. And use comments along the formula blocks (each step maybe?) to see what is happening, and where is the place where it miscalculates.