mercedes 300se air conditioning question

[benz-in-memphis]

hello fellows....i have a 1988 mercedes 300se and also my wife has a 89 300se....i love them both...the cars, that is...my 88 , the a/c compressor shorted out, i had it replaced by a very competent german fellow who runs a top notch affordable shop...i got a new one installed for 600 dollars and the air is now ice cold.....my wifes 89, the a/c has not ever been cold.just barely cool....he tested it and found the regulator to be bad...thats a themostat i think...he said 'the low side is high, it measures 70psi'......thats a hard part to install...very time consuming...when he got in, he found the previous mechanic had rigged it wrong and he had to replace the drier and something else and also install a new fan switch...also he found there was too much oil in the a/c system and he had to bleed it out and replace it..he added some freon....and the a/c still is not near as cold as in my 88 330se..its cool but not cold.....the 89 is using r12....could the compressor in the 89 be working but not working good enough..?..thats about the only component he didnt replace..i spent 650 getting the work done, but she wants it ice cold....any opnions..?..fall isnt far off, so the issue wont be critical till next spring, i guess, but i'd like to know something now?..any ideas..?..thanks very much for your opinions..