Our estimated total natural gas supply chain loss rates do not match the target loss rates of new voluntary 'differentiated gas' schemes marketing lower-emitting natural gas. Even using an upstream loss rate of 0.2%, our estimates are ~5.8 times higher, on average, than the mean total supply chain loss rate of 0.4% reported by One Future -a low emissions natural gas industry group in the U.S. -for their partners in 2022 . It is likely that One Future's estimated loss rate excludes combustion slip emissions at the point of the customer. These are Scope 3 CH4 emissions and therefore are mostly outside of the O&G industry's control, but their exclusion from supply chain loss rate estimates creates an incomplete picture of the climate impact of natural gas use. It is possible the O&G industry may be producing and delivering increasingly lower emissions natural gas, but additional downstream CH4 leakage at the burner-tip may be eroding potential climate benefits. There may be cases where widespread combustion efficiency ratings are over-estimated or idealized, and most appliances and end-uses are emitting more than intended, leading to large CH4 emissions from slip in cities in aggregate. End use CH4 emissions are comparatively understudied and require further examination for prioritizing mitigation.