Chevrolet Repair: Did I really need some of the services performed?, intake manifold gasket, chevy malibu

Question
I recently had my 2000 Chevy Malibu in for service for 2 problems.  They were both addressed at the same appointment over a 2 day period. My car has a 3.1 liter engine and has 96,000 miles on it.  The 2 problems that were addressed were the replacement of the A/C compressor and the replacement of the intake gasket (the gasket replacement was because of a coolant leak).  During this appointment, my oil, oil filter, and air filter were replaced without my saying so.  I'm sure it was not mandatory for my air filter to be replaced.  My questions are the following:  In the replacement of the compressor and intake gasket, was it necessary/mandatory that my oil and filter be changed?  How many hours do you think are involved with the replacement of the compressor and gasket? Some of the things that I question as to whether they were necessary like the oil change, filter, oil plug replacement, and air filter replacement are things that I can and have done myself.  If those things weren't necessary for this appointment, I would have had an invoice that was almost $60 less.

Answer
HI JIM, WELL LET ME SAY THAT IF YOU HAD INTAKE MANIFOLD GASKET COOLANT LEAK. IT IS A VERY GOOD IDEA TO CHANGE THE OIL TO GET ANY POSSIBLE COOOLANT THAT LEAKED DOWN INSIDE THE ENGINE FROM THE INTAKE... THERE REALLY IS NO WAY OF NOWING FOR SURE BUT AS A PRECAUTIONARY MEASURE IT IS ALWAYS BETTER TO BE SAFE THEN SORRY..YOU SEE LOWER END BEARINGS AND COOLANT DO NOT MIX..SO IF I WERE DOING THIS JOB, YES I WOULD CHANGE THE OIL AND FILTER. AS FAR AS THE DRIAN PLUG AND SEAL,IF THIS WAS NOT RECENTLY REPLACED I WOULD DO SO. DRAIN PLUGS ARE CHEAPER TO REPLACE THEN A OIL PAN. YOU SEE THE THREADS GET SHARP LIKE AND HARM THE THREADS IN THE OIL PAN..THIS IS ALWAYS OVERLOOKED...HOWEVER THEY COULD OF TOLD YOU ABOUT THIS FIRST AND LET YOU DECIDE, WHERE AS YOU COULD OF CHANGED IT AS SOON AS YOU GOT IT HOME. REPLACING THE A/C COMP WOULD NEVER WARRANT A OIL CHANGE ....NOW AS FAR AS THE AIR FILTER GOES THIS IS SOMETHING ELSE THEY SHOULD OF ASKED YOU ABOUT FIRST. MAYBE IS WAS VERY DIRTY BUT WE ALWAYS GET A OK FROM OUR CUSTOMERS FIRST AT OUR SHOP.. I AM NOT AT WORK SO I CANT LOOK UP THE HOURS TO DO THE ABOVE JOB BUT, I CAN GIVE YOU A GUESS.
TO REPLACE THE AC/COMP: 2 HOURS,PLUS 1 HOUR TO EVACUATE AND RECHARGE THE SYSTEM.
2 LBS OF FREON @ $12.00 PER LB.
INTAKE MANIFOLD GASKET LABOR  5.5 TO 6.5  BAR NO COMPLICATIONS,SUCH AS THINGS BREAKING WHICH IS COMMON... BUT THIS IS A STARTING COST.. I HOPE THIS HELPS YOU,,,,,,TOM..