> something the store managers can figure out

That's like saying the store manager should manage the store website and networks instead of the chain's IT department.

No grocery store manager is going to be a licensed refrigeration technician. Ask them if they know about basic refrigeration concepts like superheat and subcooling, high side and low side pressures, compressor oils...

Further, a grocery store wants to optimize efficiency down to the percent, because that will save tens of millions of dollars over the fleet, and CO2 emissions. A store manager hardly has the capability.