your mechanic is misinformed.
the only and correct way to check CVTF level in this gearbox is from the bottom sump nut with engine running and temperature between 35-45C, there should be a drip only and nothing more.
There is a way to check it at full hot temperature but it requires a vacuum pump, a vacuum chamber, a fluid pump and a toyota SST that you adjust to required level and use that as testing apparatus in the sump plug. I dont think that its even at dealer/showrooms in Pakistan at the moment.
If your mechanic simply removed the plug marked TC and said "set hai" then dont take your car to him for anything at all. He obviously is not informed about checking fluid level in new toyota auto gearboxes. His technique to just open the bolt and wait for something to drip from there is only good for oldschool manual gearboxes where its filled to the bolt hole, The auto is not.