I've noticed my 06 KS (ver. 6.0, stock exhaust, 93 octane) feels like it varies in acceleration performance. Sometimes it feels faster than others, even on days with similar temp and humidity. However without objective measurement, you can't be sure.
Your numbers may indicate it's really varying. Don't know about the KS but the ECU on modern cars will often pull timing, richen mixture -- whatever it takes to preserve the ECU's idea of safe thermodynamic margins. This can cause performance to fluctuate somewhat. It's usually more pronounced with temperature changes.
However my bike did three back-to-back Dynojet pulls with almost no cool down time in between. Each was within 1 hp of each other (about 140 hp rear wheel). That implies in that specific case hp output wasn't affected by heat buildup.