He is new to the raid.
55 dkp in the table (correct value)
50 dkp total lifetime in the sum, even though it's 55

version 2.1.1

Ah, figured it out. The initial entry didn't add to it. Next patch will contain a fix. The officer that distributed the DKP would have an accurate number. You can ask him to broadcast his tables to you as a full broadcast.

Curious... Any chance you happened to notice which entry didn't add to their lifetime earned? Every one of those are added with the same function with an exception of 1 (on time bonus). And that function absolutely adds the dkp awarded to lifetime gained. I'll have to poke around with that one.