weird voltage issues

Hi was wondering if anyone has had this issue before.. I have a 95 xj and at night with my lights on my dash,dome and headlights flicker when idling.. When driving they don't witch makes sense but my battery and alt have checked out good and my volt gauge is always high around 16.. I've even tried a new computer that didn't make a diff. The only thing i haven't changed is cables.. I just don't understand why its charging so high yet everything acts like its not getting enough volts.. Hope this isn't to confusing.. Thanks

Jeep was kind enough to give us very well put together stock wiring... (not)

Chances are your connections are corroded and might need a good cleaning from the alternator to the pdc. (this would cause fluctuations at idle)

I was having the same problem and a good cleaning solved this.

Also if you have the cash http://www.kelleyswip.com/electric.html this is a great upgrade over the stock wiring.

Check your grounds, also worst case scenario is you have a failing alternator.