MVER table- difference between fields GSV & UNV

Dear Sir

Please let me know the difference between fields GSV, UNV, MGV & MUV in MVER table.

One material has been consumed 10 qty in Feb 2103 and 7 in March 2013.

But in table, GSV & MGV fields are showing 3 & 7 while UNV & MUV are showing 10 & 7.

Why this difference?

Regards

Amit Agarwal