Because I only have 164 coins, and I see the stop loss drop to 0.62, just enough to lose, 164 coins.

Opening double means a 50% drop leading to liquidation, 0.9246/2=0.4623 but there are issues with fees and the liquidation price provided by the exchange will be slightly higher, so 0.47 is reasonable. Where did your 0.62 come from..