Which are the probable causes for the difference?

As executive housekeeper of an Omni hotel in Orlando, Florida, you have been made aware by the hotel controller that the use of guest supplies has been unusually high for the past three months. To investigate the issue, you decide to take inventory on May 31. These are your findings:

Value of guest supplies on beginning inventory May 1st:	$ 4,500.00
Value of purchases of guest supplies for the month of May:	$ 800.00
Value of physical inventory taken on May 31st	$ 2,800.00
The rooms division revenue for the month of May was:	$ 190,000.00
The budget percentage (expense:revenue) target for guest supplies was:	0.50%