Hello--This is my first post
I'm sort of confused on this topic so I may be wrong here, but wouldn't the margin call you are describing only happen if the equity in the account was 400$. Used Margin would be 200$, Usable Margin would be 200$, and Equity would be 400$. 200$ usable margin/10$ per pip = 20 pips. So 20 pips the wrong way and you would have margin call. It would be downright silly to trade 100k lots with just 400 in equity.
But what if one had 10k in equity, with the same leverage, it would take 9800$ usable margin/10$ pip = 980 pips in order to get margin call. So in this case with the proper use of stop losses (20 pips is 2% risk) and the right amount of equity to begin with, wouldn't it be acceptable to use 500:1 leverage without worrying about blowing your account?
I am still trying to make sure i fully understand leverage before I open a real account..the way i see it right now, it doesn't matter what your leverage is as long as you only risk a certain % of your capital (<3%) per trade and you have enough equity to begin (no bigger than 10:1 actual leverage), meaning at least 1k for mini lots, and 10k for standard.
Please let me know if I am missing something here : ) Thanks!