how do i beat phase 13 cabana event?

No matter what I do when i play this stage, i can only get ~7.6k coins each time, never meeting the 8.3k threshold to beat the stage.. i have 10 staff at max level, wait time maxed, room fee maxed, i have no idea what im doing wrong. would appreciate any help as the event is nearing its end now and i breezed through everything before this easily...