This is just my opinion, so you can take it as that.
Your bike probably was running a 14.6afr (typical harley ecm) in a large portion of your riding before you put on the PC111. Assuming the dynojet site canned maps were made using the Tuning Link software to create the canned maps, then the cruise area would be 13.5afr and above 40% throttle@3500rpm would be 13.2afr and WFO would be 13.0afr. So, if this assumption is correct, your bike (with the PC111 attached) should run cooler, stronger, but use more gas because of the richer afr. Even so, 28mpg sounds like a big drop. Again this is only my opinion, so take it as that.