I believe this was also discussed here before and was confirmed by the staff there. During our stay we made it a point to talk to the staff a lot, especially when they found out we were from the US.

How the service charge works: Most staff sign onto a hotel for a "season" and at the end of the season all the service charges are divided among the non-management staff. Most of the staff we spoke with had previously worked at different hotels prior to coming to the PH. In addition to Maldivians the staff also had a number of Indians and Sri Lankans. Since we were staying on points we weren't paying a service charge on our room, so we made a point to tip after meals.