I noticed the jump between Raines and the guys that are killed at the end of the season, but I think that there are a couple missing from the last episode. Mason says toward the end something to the effect that jack had killed 7 hostiles before the assault teams had arrived.
What I've read is that there was an extended shootout filmed but cut for time constraints.
Most of the time I only count deaths that are shown or at least some visual evidence is shown. Also for the final episode the shootout was shown all at one time so really there wasn't any way jack could have killed anybody else.
Mason's line I'm assuming is just a boo-boo by the editors. Good catch though