Sorry for the late response. So, I've been reading up on ΔT. Read some 6-7 articles and everywhere it said that the differential should be between 16 - 22 °F. In my case, for yesterday the temp was 31.5 °C approximately equals to 89 °F and the vent temp after about 30 mins went down to 15.1 °C (this was at 16 °C and lowest fan speed). The differential here comes out to 29 °F which is out of the 16 - 22 °F range mentioned in the articles I read. If I go by those articles the vent temp should've been somewhere around 22.7 - 19.4 °C, still out of the acceptable range.
I don't have the power consumption metrics, I think I should get an amp meter to be absolutely sure about the AC. But this seems to correspond to how my AC is behaving, what was the room temp during these readings? But I also tested the 1.5 ton Gree downstairs in the dining room, with a small gallery opening into the lounge. The temp in the room was around 29 °C after about 15 mins the vent temp had dropped to 10.8 °C. So I am still a little confused about the vent temperature 
I will check the amps during operation and hope that it is working as it should.
Yes, I checked the temp after 15 mins while running the AC at 16 °C and lowest fan speed. Following is the vent temp it achieved. I kept running the AC on full speed after this for an hour and the temperature in the room dropped to 27.8 °C (But this was in the night, will run a test in the afternoon over the weekend and will shared my feedback). For reference, I am attaching a pic of the room where the AC is installed.
Shared the performance figures for yesterday, what do you think?
It's a new AC installed in April 2023, filters are clean, I checked when I shared the last update.
