I thought that you all might find this interesting - if not useful. When I bought my car in Oct of 2016, it had just had an oil change. I have no idea what brand or weight of oil was used. My car seemed to really like to drink whatever they put in it. Over the first 5,000 miles or so, my low oil light went off three times - each time requiring about a liter to top it off. I was worried that I had bought someone else’s problem child (despite a great carfax showing very good service history). I took it to my local Audi dealer for it’s first oil change, and I think that they used Castrol (can’t find the receipt right now). After the first oil change, consumption was reduced by about half, but was still more than I would like to see.
At my last oil change in July 2017 - I bought the oil change kit from ECS, with Pentosin High Performance 5w40 synthetic. Just changed the oil last night after 9,500 miles (Pentosin again), and the oil was still pretty clean. More importantly - it had only consumed about half a liter in this time frame!
My car had very low (35,000) miles on it when I bought it. It appeared to have been used as a city car in SoCal. It now has 60,000 miles on it (25,000 in 16 months). I don’t know if it was the oil, or the change in usage and driving habits, but I’m going to stick with this oil just the same.