No more passing gear, problem solved
After an ECU software update done at my last Service A interval the acceleration and passing gear just wasn't the same. No matter how hard you press the gas it would more slowly get up to speed and if you want the transmission to downshift you had to do it manually with the gearshift.
Well, I'm not sure if I blame myself for not catching this sooner but the good folks at RBM Mercedes in Alpharetta helped me resolve this problem and it had nothing to do with the update. Apparently the techs had pulled back the flooring around the gas pedal at my last service and didn't lay it down properly. It created interference that kept the pedal from reaching full depression. It's not obvious to spot at all as the flooring lays perfectly in the wrong ridge.
Not sure how many other Atlanta Interstate owners there are but my advice is never have your Sprinter serviced at Atlanta Classic Cars Mercedes dealer. This issue and a number of others were introduced by a simple Service A interval. They are new to working on Sprinters and just don't have the techs for it. I reported this issue right after my service and they told me it was perfectly normal on two different test drives.