Service members should only get charged for the hours/days of work they actually miss.
DoD Instruction Number 1327.06 (dated 16 June 2009) requires that service members be charged leave during federal holidays and other days the member would already have off, if that member is taking leave during that time frame. For instance, if a member wants to take leave after work on Thursday and return to work Monday, the member will get charged for 3 days, even though they already had the weekend off. The same is true for holidays. The government advertises that service members get 30 days leave per year, but unless the person is only taking leave from Tuesday to Thursday, they will get charged for time they already had off.