I was to have a 15 seer unit installed and in reviewing the manual it states that I have a 14.5 seer unit, should I question this with the installer?

I really wouldn't worry about a half seer, but it can't hurt to mention it to the installer and see what they have to say. The savings of a half seer will literally amount to a couple of cheesburgers and fries a year.

Differance=.5 seer

There is a price difference between a 14.5 SEER and 15 SEER. The 14.5 SEER is about $400 less than the 15 SEER. If you paid for a 15 SEER, you should get a 15 SEER. I would request the price difference between the 14.5 SEER and 15 SEER to be immediately refunded. On a personal note, I would recommend that you do not call that HVAC company for any maintenance or repair in the future.

As for the SEER difference, you will not notice any kind for savings in your electric bill.