Are you asking if 75 degrees inside on a 95 degree day is good or are you asking if you measure your indoor air temp before going into the ac compared to the air coming out of a vent is a 20 degree difference?
Probably not. The better way to look at it is to measure the air temp where it is going into the filter and then measure the air where it is coming out the closest vent to the AC and see what the drop is there.
the reason I ask the unit has a very small leak in. I have to put 15 ounces in it every 2 years. Is there a refrigerant that is a direct replacement for r22? I know R22 is getting phased out and being replaced with R 410A which you can buy without a license. The unit is 7 rears old I don't want to replace it.
It probably needs freon, but the way I described to measure temp drop gives a better idea of what is happening than to compare outside and inside temp. What temp was the inside air when 75 was coming out.