It is right.
He has more girth than you, and girth displaces more area than length so he has a larger cock than you when its all added up etc.
If you have not great length stats but great girth you can easily catch-up to someone with massive length and small girth.
This volume thing, is the real size IMHO and when we see guys in ���� with 9 inches of lead, and say 5.5 inches of girth, when compared to say 8 inches and 7 inches girth it will fall behind.