Yes, thanks, and I have considered going the whole MODBUS card route to get more data and control also.
And this almost could just be something local in the outside unit that if the outside temperature is >~10C (so no danger of frosting up) impose the lower limit.
The 5A limit worked fine for DHW from May until now, smearing demand nicely, and allowing my older grid-coupled battery to cover it entirely, and merely slowing generation of DHW a bit.
Anyhow thanks for the observation!