The pressure system is different for the older bands which is why the fact that one holds 4cc's and one holds 9cc. It has nothing to do with the size. The benefit of low pressure bands like the Lapband VG, AP and Realize and Realize -C bands is that it allows for more precise adjustments.
By the way there is no such thing as an 11cm Inamed VG, it a 10cc.
These are the sizes for US bands.
Lapband 9.75,10= 4cc
Lapband VG= 10cc
Lapband APS= 10cc
Lapband APL= 14cc
Realize band =9cc
Realize band -C =11cc