The other day I noticed my remaining recording time was getting low on my 722, I went in and deleted 5 episodes of fringe which are 1 hour each. Before I done this I had 7 hours and some odd minutes, when I deleted it I only had 10 hours and some odd minutes. So I went in and deleted another 1 hour show and only gained 20 minutes. This is all HD by the way. Is this normal? is there a buffer time the 722 must have before it gets the whole time back?