Thank you for the reply.
I will continue to investigate whether it is custom procedure to add new 1.5 kg coolant (refrigerant R-407C) instead of reusing the old (I suspect I'm paying for new all though company replacing the expansion valve has in fact reused the old coolant).
One more question.
It took the company 14 days to realize they had by accident put on 0.5 kg to much coolant, so a total of 2.0 kg where the Greenline HT Plus C9 should only have max 1.5kg.
So it has been running 14 days with too much coolant which has triggered the 'High Pressure Switch (HP)' error many times.
What is the risk that this has damaged the compressor?
Google'ing about this it seems that too much coolant thus too high a coolant pressure can cause the refrigerant to enter the compressor as liquid instead of gas causing damage.
The compressor is still running and as far as I can tell sounding normal.
But is there a risk that this has shortened its life due to excessive wear?