external dvr storage

[ramapochik1]

I have the motorola qip7232 2 and the wd my book av 1tb external storage hard drive.  recently it seems the percentage used up is off.  I only have 1 thing on there and it is the very end of an hd show that i missed (about 5 min).  The used space percentage is 2%, which seems a little strange to me since there is really not alot of stored recordings. I'm not sure why it's already at 2%.