This  is  common

That would be unusual but in this case his Squad Power of 4,118 is pretty inline with that amount of max damage. 

Since he is in the Final Bracket as well there is nothing particularly unusual about this especially considering his win rate.

I wouldn't worry about the 1.3 mill damage.  Like the two previous posters said, that's common.

Speaking of tournament mismatching.  I've demolished 1k to 4k+ players with a 800 power squad.  The level of the players do not matter in tournaments as the point system is based on number of kills not damage.  My noob account is super OP.  I only have 3 mech slots:

Slot 1 - 2* Lancer with Auto Cannon 2

Slot 2 - 2* Paragon with RPG

Slot 3 - 4* Killshot with Carbine 8's

So I have 2 non upgraded mechs and a beefed up killshot.  The bots I am put against go down in 3 bursts.  I can dash most bots for an insta kill.  A typical match gets me 25+ kills and 500-600 points.  I can kick the crap out of any 4k pwr player getting 200-300 points per match.