wide band readings and infrared exhaust readings

Looking for some info on exhaust readings I tried to interpret. Have a FI Mustang, 1968 conversion 302 engine. When I connect my wide band to the bung behind the O2, I'm getting 12.3-12.6 AFR at 2000 rpms sitting still. I'm also getting from my exhaust analyzer(4gas) a reading of .39% CO. At idle this vehicle is showing .44% on the 4gas, and 12.3-12.6 on the wide band. They are at completely different ends of the spectrum. Can someone put this in perspective for me?
Thanks.
Street Perf:mad1: