Iginition coil, spark plug and window regulator on 2004 Lincoln LS

Hi, can you please tell me an estimate to get replace all spark plugs and ignition coils plus the drivers side window regulator with labor at $60/hour? Also is a coil pack and ignition coil the same or is the "pack" all 6 coils?

Asked by for the 2004 Lincoln LS
Your 3.0L V6 has a single coil for each cylinder, and the coil needs to be removed to replace the spark plugs, so there would be little if no extra labor to replace the coils when replacing the spark plugs. The time to replace the plugs is about 2.5 hours. $60.00 an hour seems low for your area, you must be getting or giving a good deal!
Mind if I ask, why are all the coils being replaced? This is not common and normally not necessary.
If 3 out of 6 failed, then I would agree, replace them all.
The mechanic said we should replace all of them instead of just the 3 bad ones because if I only replace those three the three older ones will go bad soon because they will have to work harder than the 3 newer ones, I don't know much about cars so I don't know how true this is but I need my car fixed and would rather do this all at you think I should only get the ones replaced that are bad now?
Thank you for letting me know, I feel a little better about getting the work done =-)