Air Conditioning - Hot In Houston

Still having problems with insufficient cooling in my house. I had an a/c tech come out and take temps from the room air entering the coil (where the squirrel cage is at) and that air was 80 degrees, he then measured the air exiting the coil and that temp was 51 degrees...can anyone tell me is this coil performing like it should...? (outside temp was 97 degrees and the attic temp was 118 degrees.)

After he took these temps he said the coil was fine that my duct work was funky...he said the transitions in my ducts need "triangle shaped duct board" for better air flow...can anyone give me an opinion on this...I've read that duct board really isn't a good substitute for this....

(He used a digital thermo and punched a hole in the top of the air handler and inserted a lengthy wire to get his readings).

Exiting by the coil is 51, and exiting the duct at a register is - what?

29 degrees is a lot, may indicate low air flow. But could also be correct if everything checks out.

Ec is correct, what are temps at defussers?

In and out of coil tells you what it is doing. Out of coil and out of defussers telss what maybe up with duct work.

What do your transitions look like?

Before you ask, a transition is used to reduce duct size and/or split on run into 2 or more.

Do you feel comfortable with checking which speed the blower is operating at?

The register closest to the coil (duct is about 3 1/2 long) during the heat of the day is 62 degrees...I have another register ( both are in my living room) that's about 15 ft. from the coil and it reads 71 degrees, again during the heat of the day.

Transitions are metal Y's...one transitions into a 6" duct from a 9" duct to a small 125 ft. sq. bedroom. This duct is transitioning from that 15 ft. duct that goes to my living room that's 9" in diameter all the way to the register that's blowing 71 degrees.

How do I check to see if my blower is set at the correct speed...?

Sounds like you have insufficient airflow number 1 as your temperature drop is too much but according to your last post you are increasing temperature substantially from the time it exits your coil until it enters your living space that means your picking up heat is your ductwork in your attic or crawl space/ basement, it sounds like attic. Is your ductwork properly insulated and is the insulation in tact is your attic ventilated I would investigate thes things and post back