Can anyone assist with the following

We have a Mycom Compressor that runs to freeze down a spiral tunnel and at the side of the Mycom we have a Grasso SP2 compressor runs to freeze down a Polobed for ice lollies. Both compressors use the same liquid pumps, Surge Drum and receiver etc

The problem I have is both compressors are controlling at the SP Value but at the tunnel and polobed it is -22.0 when it should be -44.0. The only thing i can see different is the liquid pump pressure is at 0.8bar when we are used to seeing it at 1.75bar

If you require more info i will try but i dont have a refrigeration back ground