Hub dyno Vs Roller dyno Vs tune
 

Can anyone enlighten me about the following dyno and power/torque results?
I have an air to air Vortech supercharger with ECUTEK tuning.
I just swapped out my old (cat less) Invidia exhaust system to an HKS system with Invidia high flow cats and therfore had to be retuned.
Since the most recent tune I seem to have more "mid range" power (as my shop explained to me) but it seems lacking up top compared to before.
The car seems to "pull" much better in mid range RPM's compared to before the exhaust system change and tune, but seems lacking up top now.
I do not have a comparison of this most recent tune on the hub dyno, only the roller dyno.
Can there also be such a big difference in up top power on a hub dyno compared to a roller dyno or is this not an optimized tune?
Please see pics.

There can be a difference simply based on the weather. I wouldn't worry about it so much not only is your car different but. Different day, temps, dyno, barometer, calibration, tuner, tune, wear n tear, etc etc. In a lab and with both calibrated they should read very similar.

You made a change in your exhaust. That will effect where the engine makes power.

Is your latest tune 257kw or am I reading that incorrectly