Volt Meter Gauge Not Right?

I have a 1993 Cutlass Supreme SL with the 3.1L, well today my alternator was workin pretty crapy, smelly. noisy. barely giving me 12 volts. so i got a new one. After bitching for about an hour. i got it done. And everything works fine. As always though the volt gauge always reads just under 13. like 12.5 or something. Well i plugged a meter into my cigarette lighter and its reading like 13.5-14.2 So im pretty sure the volt meter on my inst. panel isn't set right. Any info on it. can it be calibrated, or does everyonesn read like this. Im totally at my wits end about it. sometimes it reads even 13. on cold days when i just fire it up its over 13. but i dont feel its correct. So any help would be GREAT!!!

I really think this could be a tough one for you to easily solve. you'll need a wiring diagram. trace the circuit to it's ultimate source, and in between those points look for anything that might cause voltage drop, i.e, corrosion.... I find it unlikely though that your going to find anything, as the signal for the stock meter is probably coming for the PCM, and any external wiring associated with the circuit would show up as other symptoms, like over charging... also your new alternator has an internal voltage regulator, so it's brand new anyways... If it bothers you a lot... try wiring it differently, like tap your positive feed into your lighter circuit, and ground to anywhere under the dash thats metal...

its not that big of a deal, i was just curious if there was anything i could do about it. Thanks anyways for the help