for all you intelligent ones

Three guys walk into a motel to get a room for the night.
The attendant, a new hire, is unsure how to charge three people for one room. So he decides on $10 each, totaling $30. Each guy pays with a $10 bill.

The manger comes to check on the new attendant. He informs him, the room is $25 regardless of number of occupants. The manager gives the attendant five $1 bills, instructing him to take the men a refund.
The attendant, knowing each man paid $10, can’t decide how to split $5 between the three guys. So he pockets $2, gives each of them $1 back.

Now, each man paid $10 minus the $1 refund.
10-1=9
At $9 a piece, the 3 guys spent $27 on the room.
$9×3=$27
The attendant kept $2 for himself.
$27+$2=$29

Where’s the remaining dollar?