The only conclusive way we can tell that is after 3 GPsCHT wrote: did you compare the drop off between button and lewis? Might be interesting to see who will have the upper hand this season when it comes down to tyres.

Testing variations dont just include Fuel weights or different compound tyres.
To an outside observer, Hamilton and Button could be on identical fuel weights with what appear to be the same tyre. But one tyre may have have 10 laps on it and appear none the worse for wear. This in itself can cost over a second a lap.
One thing is certain though, that in either Lewis or Jensons hands the car appears to be very consistent.