Tip: while researching the Mercedes 236.15 Fluid Spec, I learned that Shell sells a MB 236.15 approved fluid under the Shell label. https://bevo.mercedes-benz.com/bevolisten/236.15_en.html
The dealerís list price for the 236.15 approved fluid (called ATF134FE, #001-989-77-03-09) is $24.50/L. I called a somewhat local Shell Oil Distributor, and was given a price of about $77/case-of-12L (or $6.44/L) for the Shell ATF134FE. That is about a 75% savings in comparison to buying the fluid from the dealer! Both are MB approved fluids and should function identically where it is specified.