box fill using mc-hl

[103FLHX]

i understand 314.16 (5) but what might be a little confusing is when using an mc-hl type cable say a 3c #6 which has 3c #12 bare ground wires in it. would you only count or give a single volume allowance for only 1 # 12 ? even though you have 3 #12's coming in from the same entry point