Fujitsu AOU9RL2 not loading up

I replaced an old Fujitsu AOU9RL2 10 days ago with a new identical model with indoor unit. It worked fine for 1 day then it started to degrade. No alarms. Cools but barely. Fellow tech added 8 oz of 410a two days ago but no success. He ran unit in the test mode with no change in cooling, pressures, or temps. Today I ohmed out the 3 sensors outdoor and the 2 sensors inside, they checked out ok. Compressor ramps up at start up from 45 to 113 HZ, suction saturation temp goes to 40F, stabilizes for 15-20 seconds, and cooling works well like it did when I installed it. But then comp slowly slows down below 90HZ and suction saturation temp climbs to 55F. Suction superheat is too high, single digit originally is now 20F plus. Supply air temp indoors is 67F and return air is 78F. Any help would be appreciated. Thanks.