This may be more of a contractural question, but I'm thinking the floolwing.  If you took off from work the time would have to have been taken from some place.  Your employer only had vacation to take from so they did.  In some companies they have sick time, personal time, holiday time etc.  The companies I'm familure with would have taken vacation time since the other days weren't granted.  Some times for good reasons (maybe dr. appointment) they just granted me the partial day to take care of an important issue.  Of course my job still had to be done which meant I might have worked extra hours or Saturday.