Additions 2 measure oil in diesel – consumption benefits?

Hello Together, how are your experiences regarding consumption reduction by the addition of 2 measure oil to the Mutijet diesel engines? Drive the Croma Multijet 16v with diesel particulate filter and would like to start with it now at a KM of 70,000 (250 ml per tank filling). When you deal with the topic some report a consumption decrease of approx. 0.2-0.5l/100KM. At the consumption decrease I have doubts, but not about a rounder and smoother engine run. he feedback I am happy. Greetings, sedicivalvole m