This is what I measured yesterday 4pm 99f outdoor ambient. With fluke probe, indoor return air ceiling grill at 78.8f, supply air grill 63.0f. Indoor humidity is 49%.
Outside, liquid pressure at 150f (pressure temp 82f) liquid line temp 78.2f. So 4f subcool. Suction line Pressure at 67psig pt of 40f. Line temperature 49.8f so superheat of 9.8f. Discharge air out of the condenser fan was 106f. I looked around the condenser for big temperature drops indicating a restriction but couldn't find any. When it cools of in the fall/winter I might change the filter drier in case there is an obstruction there. Now that I'm typing this I realize I forgot to check amps.

All I know is my house is as cool as before and the power usage has gone down. If it all keeps working I'm not replacing it b/c it is using less power than the typical 16 seer I'd replace it with.

The liquid line temperature reading is very concerning. Follow the liquid line back up into the condenser and find out where the restrictions starts. Various brands are using liquid line driers inside the unit now. So make sure to look around in there, and also make sure you weren't doubling up on filters. With a 99 degree ambient I expect to see 105 maybe 110 degree liquid line.

/Redacted suction comments, misread last post/

I'd like to see more of a drop in the vent temp though. 15.8 drop wouldn't make me happy as it would be really hard to get the temp down inside to a comfortable level. And as mentioned that liquid line temp is just plain weird if that's the actual temp of it. I'm doubting the test equipment more than anything else.

What is your thermostat set at?

Temp probes and test meter are Fluke. Keep the house at 78, wife sets it to 77 when I'm not around. Temp drop would be better at plenums b/c equipment and ducts are located in an unconditioned attic and over 100f. I'm not going up there to measure this time of year. I know its way off the charts for traditional a/c, I went to school , have had my master license for 14 years, repair 5 air conditioners a day everyday. Its a match up thats not supposed to happen and fortunately I had great results despite not fitting into normal operating perimeters. Currently its cooling 1200sqft comfortably and using noticeably less power than before. Might I suggest someone else try it?

Yeah temp drop is probably better depending on how far your closest duct has to run. Lots of heat gain to the ducts in the attic. Our attic runs around 140* in the summer when it's 105*+ outside.
Makes me think more about back age units and running the ducts under the house on pier and beam houses. Much less heat gain there.

Still trying to figure out why your liquid line temp is so cool though... Odd combo but it's hard to argue with results...

I do wonder how the system would work when cooling to normal inside temps. 78* is pretty warm. I would be miserable at that temp. I know I was until I replaced our undersized system. We keep ours set at 73* which puts the warmest area of the house around 76*. When it's really hot and it's 105* to 115* for more than 5 hrs a day I bump it up until around 10 pm when it starts to cool off a little. Even at that our elec bill is around 50% less than it was with the undersized system that struggled on a cool day when it was 95*.
Yes weather here sucks and why we can't wait to move.

Thank you! for your comments, I have just a similar situation.

Its is such a helping discussion forum.