A/F mixture, how to adjust

I have a pro chamber and kirban adjustable coming next month. But right now I have my laptop hooked up to my innovative lamba cable and my A/F ratio is going from 13.5 when cold to between 14.5 and 16.75 when warmed up. That is at idle. I think that is too rich at cold temps and to lean when warmed up. The numbers jump around from 14.8 to 16.3 and I would like to know if I can adjust those numbers with the stock regulator(non adjustable)? If I retard the timing will I make a richer mixture or will the computer compensate and keep the mixture lean like I have been seeing.

The lambada cable is from innovative motorsports part# LC-1 it comes with a wideband O2 sensor, software and a serial cable to attach your computer/laptop. Great product, plus you can buy other accessories for it to measure other parameters of your engine. Like water temp, oil temp, EGT's, and etc.... Here's a link to the LC-1 http://www.innovatemotorsports.com/products/MTS.php
If you do not already have a wideband and A/F meter then I would suggest getting the XD-16 with lambada. If you already have a wideband you can get the LC-1 cable without the wb sensor and get one of the LMA-3 for expanded measuring. It's cheaper than most tuning software\hardware out there.