How are you measuring A/F ratio on DS? Using DS data and not a WBO2(wideband O2)?? If so, it's useless info. Direct Scan has no way to know what the actual A/F ratio is since it does not use a WBO2 input. It only shows what it's estimate of commanded A/F is. A guess at best.
There are lot's of good data points available in DS for tuning use. A/F is NOT one of them.
You'll only get good useful A/F ratio data from a WBO2