Yes--the only way to tell if the system is working right is to hook up a low pressure and high pressure gauge respectively. That will give the proper idea of what is happening.

Also, it's possible that the climate controls are malfunctioning and causing heat to get through to the passenger compartment, destroying the cooling ability of the A/C system.

The best way to start is to see if the system is making appropriate pressure.
--
Chris Herbst
1992 745, 68k

And others:
93 944, 150k
90 245, 110k
88 744, 160k
87 245, 185k