That might be normal. I noticed the pressure on the suction (low) side rose but eventually dropped after I introduced freon into my system. Troubleshooting the a/c system without knowing what the pressures are on the low and high side is going to be very difficult. It may just be that you are underserviced or overserviced--nothing more.

When I had my a/c troubles a few weeks ago, I didn't want to hear Arthur Dalton tell me that "gaugues are required for a proper diagnosis;" but, he was right: Without knowing the pressures, it's going to be hard for you to get help from the guys that know what they're doing.

Buy the gauges. It will be money well-spent. You're only looking at 50 bucks. If you blow a compressor out on that car because the system was overserviced, I guarantee it's going to cost you more than that.

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1993 400E, 256,000 miles (totaled)
1994 E420, 200,000+ miles
1995 E420, 201,000 miles