DynoJets have built-in weather stations that measure ambient temperature, humidity and altitude to make proper SAE corrections. But the nature of inertia dynos do tend to not be as accurate as steady-state eddy-current dyno.
The 300 graph does look slightly higher than others I've seen. Most significant though is with improvements in torque. HP's up +25%, however, torque is up +40% (which is really what accelerates)!