You have two measurements with the same time stamp.

Checking your clamp meter would be a good idea. Also amp measurement must be made together with voltage measurement and you have to check that the test voltage for your compressor matches or you have to compensate like I mentioned before.

I suppose you have lots of sunshine on the evaporator to evaporate at +9.8°C with +8°C ambient.
First define what you want to optimize.

The ZH line can work up to 75°C condensing (about 35 barg) so if you want to optimize your water temperature you should try increasing your condensing pressure but check with your Copeland wholesaler what is the maximum discharge temperature it can withstand.

If you want to optimize the time it takes to heat up the 600 liters to a minimum temperature you should try to increase your thermal load in the evaporator.

Both have pros and cons so ask the customer what he expects of the system and try to comply. Leave optimization work for a lab!