"Ichiban:
From the radar plot submitted by training wheels, if the 353 is ground speed, it would be slower than expected at FL363.
See the nearby Emirates 777, UAE 409, MEL-KUL. The 777 is at FL360 with a ground speed of 503 knots.
An A320 is not 150 knots slower than a B777."
Yeah a fair bit slower than expected.. but still not impossible when you consider that they may have been hitting best rate of climb to try and clear the weather and possibly pushing into 130kts of headwind.