These are many questions without enough information:
"Insane loss bug"
I read your post several times and didn't find info about a "bug" you have experienced. Can you give us more specific info on that?
"it does not fix my average prices."
What do you mean? When you use averaging, the EA shows the average price of the position at the top of the chart. Do you think it was wrong? What MT version you use. Please provide a strategy for additional tests.
"I have terrible losses because of this"
What is the connection between the averaging and the loss? What results you received on your MT backtest and on your demo test?
"Only 1 night of trade me cost me 190 usd"
We don't have idea how many positions you opened, what was your entry amount, Stop Loss... What was the Max Drawdown of the backtest? Please give us more info.
"How to fix this?"
What exactly you want to fix?
"How to 100% prevent losses when adding new lots?"
Adding lots will not produce losses. You may have loss only when close lots.
"Why is this happening?"
Many reasons are possible and we cannot answer you without additional information. Most probably: you opened too many positions, the entry amount was too high for your account, your SL was too far away, your expert trade more frequently than you expected.
Please provide your strategy and MT screenshots or logs so will be able to answer.
Second? It looks like the fifth.
"Why are your ForexSB strategies so slow when tested on MT4?"
Mhm. You probably speak for your strategy. I normally use strategies that do not require tick testing and produce equal results when use the other MT testing methods. (By the way, from where MT takes ticks?) Our goal is to make strategies that can be reliable created and tested in FSB Pro. We use MT tester to confirm the expert work for a short period of time (several entries and exits). Later we test the EA on a demo account (or on real with minimal entry) for several weeks.
"This XML takes me 5-6 hours of tick test for 1990-2016"
You must have several gigabytes long tick file. I don't know what do you expect. What is your time frame?