Arrived on site customer complained the unit was not cooling. Found unit to be low on refrigerant and have a leak at the evaporator coil. Advise customer that they should repair/replace the coil Before adding any additional refrigerant. Customer stated that there was an NTE $400 on this job. He said that they wanted some refrigerant but not to exceed $400 including service charge. I explain to the customer that I didn’t feel like adding a partial amount of refrigerant would make enough of a difference in the cooling to justify the expense and that they should either put that money into window units or replace the coil. Customer insisted that I add 2 pounds of refrigerant. Added 2 lbs of R 410a.