Well, he has more frags than you. Also he has more covers, defkills, flagkills - all of which by itself gives additional points (IDK how much - never bothered to look) to basic 1frag=1point.
Cover means he shot somebody close to flag carrier, defkills means frags near own flag, flagkills means how many times one shot enemy flag carrier iirc.
IDK if grabs give you anything (again, didn't bother to check it), but capping flag gives variable amount of points, basing it on the distance you carried flag inb4 capping it, whether you were covered by anyone, or were alone, or something like that.