So if the performance data is based on 230v a/c power supply & the customer has 245v a/c power supply that would make a slight difference to the compressor speed & amps drawn but would also result in slightly better heating performance.
But the problem is not flat out performance in this case.
The basic problem that the customer has noticed is that the compressor does not ramp down & reduce power input at low load conditions.
What is the point of having an inverter system which should save energy by ramping down the compressor at low load conditions if it actually only works to the same control stratagy of a fixed speed compressor ?