The reversing valve changes the flow of refrigerant making the outside coil the evaporator and the inside unit the condenser coil.

First the coils all need to be cleaned both inside and out. 

Apparently, the coil had been replaced in 3 of them. 

In addition to the items you mentioned, I have the HVAC serviced every spring including cleaning the condenser coils, lubricating the motors as needed and checking the refrigerant levels.

Vinagear scrub the walls and ceilingsOil based Kilz paintClean the flooring with vinagear Ozone machine when not working in the propertyClean out the duct workReplace anything that is fabricReplace AC filters and run constantly and then replace againScrub the fridge coils and any surfacePaint it againClean it againRepeat process as needed (it sucks and it takes someone moving in and absorbing the rest of the smell)Whatever you do don’t turn of the electricity to the unit.  

The “issue” is pipe sizes and a leak in the evaporater coil.

They have no real estate experience and are just going off of general perception.The next big problem is that he is supposedly ordering a new HVAC with the A Coil and outside unit that he wants to install himself.

I also will get a new outdoor AC unit in the spring as the hail destroyed the coil on my old one. 

Just used a miter saw and trim nailer for the first time in the past couple weeks while working on my personal residence.  

The tenants don't change or clean their filters, the coils get dirty and we have to spend $150 to clean the coils.