The school called me back and confirmed that is what they did...they used the credit from the housing from last year and applied it to the last payment and any remaining credit will be applied to her bill this coming year. She explained a lot of people asked for this saying under the circumstances it would be a huge help so to make it easier from them they just went ahead and did for everyone that pays monthly.
The one thing about going to a smaller school ... they tend to try to make things as helpful as they are able.
The thing is I took out some money from the 529 plan to pay for part of this expected payment . ..ah well will just transfer to savings for next month when I start paying for her final year.