HE'S PLAYING RENO SINGLE DECK! Sooner or later, usually sooner, you're going to be stuck with negative counts playing single deck.
BTW, out of curiosity I did some basic sims with the restrictive "Reno" (D10) single deck rules... and the results were worse than I expected. Better than play-all in a shoe game, but worse than a decent doubledeck game with good penetration. And to think, when I was bumbling around Reno, I thought I was playing the cat's meow of card counting.