When I placed buy orders and stop loss orders for TSLA, it happened that, having in mind the time when orders get completely fulfilled I bought at a much higher than MKT price at the moment and sold much lower than market price. Maybe it was that way because of the book cueing that our fellow friend several posts above mentioned. I dont know, I have been confused since then.
When I place orders, I do them on when the market its still closed and when they are executed, they are fulfilled at a higher price than the price that appears in my cellphone app for that particular stock in that exact moment. Next time it happens, I will tell you.