Memory Questions

This is just a curiosity question. I have a 16 GB card installed. I have the Clip+ loaded with 880 songs. The info menu shows

Version V01.01.05A

Memory 7548MB

Free 91MB

Songs 880

Audiobooks 0

Podcasts 0

Voice Recordings 0

FM Recoordings 0

Power 100%

SD Card 15185 MB

Free 15185 MB

Note the free memory on the SD Card. That can’t be right. It shows 40 MB free when I look at it on the computer.