Recently installed a wideband (along with headers/new exhaust) on my '95 Roadmaster and was noticing that the car 'hangs on' to enrichment for a short time even after lifting the throttle (I'm assuming this is normal behavior) and will also go rich (12:8/13.0:1 afr) with increased load on the interstate (i.e. fighting a headwind or climbing a hill) but it does not show as power enrichment on my logs. This is happening at less than 22% tps and below 50 kpa map.
Wondering if anyone has encountered this before and if it's worthwhile to try to tune it out (better highway mpg)?

Also had to remove the egr for the new headers and thought I had tuned it out but I still see blips of 15% egr duty cycle on my logs - is this anything to be concerned about? The system is physically incapable of doing anything, vac & electrical are unplugged and blocked off.