Mark....You've got me wondering.....My coach is right on the full mark with 24 quarts of oil including a filter change. My manual says 20 qts low, 24 qts full and 28 qts with a filter. The filter only holds two qts.
I've been running mine at 24 qts since the first oil change. The oil has always been right on the full mark.
I have the notch on mine, but it's another 2"-3" above the full mark. Awaiting a reply from an email I sent to Cummins.
Don & Mary
2019 Newmar Dutch Star 4018 (Freightliner)
2019 Ford Raptor