I seriously doubt that adjusting the expansion valve will help here. The block style expansion valves are not designed to be adjusted anyway. I have adjusted them before but never had much luck and they usually leak after being diassembled.
If you have an expansion valve problem you might as well replace it as you will have to remove it or at least discharge the system to make the adjustment.
Whether or not you do have an expansion valve problem can be determined by an experienced tech by monitoring the system pressures.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician