Yep. I have a few guesses. First, is that the torque falls off sharply at the top end. At the dyno the torque can peak at 360lbft at like 3000 rpm. But the small factory TD03 turbo can't feed the motor enough at the top end. If I used a type r turbo like the TD04 then the torque would shift higher towards the 4000-4500 range and probably pull way harder at the top. So because I am making well over 300lbft at 1500-1800 rpm, I won't get great ET without tires, suspension, and so on. Plus, its an auto with an open diff, unlike my civic.
The second guess is once I get into 3rd and 4th, I begin to heat soak quite quickly due to the factory inter cooler.
Im not gonna bother taking it to they dyno since the data log shows everything is gucci.
But based on the math you suggested it adds up.