Bunk ac freightliner century class

About a month ago the compessor had built up pressure and relived itself from the pressure vale in the back.the shop flushed the system and replaced the expansion block but not the compressor

 

Should i have the system reflushed again

 

Just a update removed the back unit in the sleeper replaced the coil.clean box.replace the thermostat. Shop pressure tested and recharged the system .we let the truck run for 8 hours to make sure it worked.back on road started doing it again.

 

I turn temp control all the way red in the cab and in the sleeper.it started freezing up again.only the main line off the comprssor back to the sleeper it starts freezing up at the back expansion block the proceed to the main unit