Upon loading the game, the total in the top left already shows the offline amount collected, since that collects while you weren't playing:
At this point, hitting the Collect button wouldn't affect the total, since the earned cash is already being displayed.
The x2 button shows what that total accrued could be if you choose to get the bonus:
After the ad the additional amount is added which brings the total accrued to double what it could have been :
