What is the difference between CALL FM in BACKGROUND TASK and UPDATE TASK?

I guess, if I called 2 FM in background task, both of them will be executed one by one.

if I called 2 FMs in update task, only the last FM will be executed.

Isn't it?

I got a scenario here, I use a export to DATABASE to flag sth. This flag will be checked in a EXIT, which will be called several times. This part of logic will be also called in background task FM. How can I delete this DATABASE flag after all the execution of the program?