Dynapack are known to read considerably lower than other solutions, and they read "at the hub" there is no tire friction ...
As a side note, my BRZ has a similar progression as 6packs, and it gave similar results on a dynapack, In japan, from stock to the V1 HKS supercharger.
Base Dyno stock and after full HKS exhaust + HKS EL Spec-R manifold + Tune. (it was really hot and humid that day, 98 degrees f and 91% humidity)
And same as 6pack's V1 HKS supercharger, also has HKS flywheel + clutch
Yes with a dynapack, stock, 200hp at crank reads abot 148hp at hubs ... but as long as you keep using the same dyno in the same conditions, what matters is the delta.
So nothing abnormal here, and yes this kit pulls hard ! V1 or V2 if done properly its an animal, reactivity is just astonishing, its instant power ...