withdrew bitcoins but made money?

can someone explain how?

I know bitcoin fluctuates, so should I only withdraw money on days the bitcoin market is up?

please, somebody help me out here im so confused.

only reason is bitcoin fluctuation

if you know it will go up tomorrow, withdraw and of course buy bitocin today and sell tomorrow question is how do you know bc will go up tomorrow?

similar thing happened to me many times, opposite happened also

so basically i should cash out ONLY on days when bitcoin is up.

not necessarily. when you cash out from a bookie, usually when they actually pay you is the going rate for bitcoin. if you want to sell right then you should only gain/lose maybe 5 dollars max. but if you wait the choice is yours. 

which is good if you are withdrawing money

but bad if you are depositing 

I deposited 1000 at a book and got credit for 988 or something

so remember what circle's pros and cons are