61 K miles for 1 quart of oil. That is an extreme low oil consumption. It may sound strange, but to have a little oil consumption between 0,05-0,08 L/1000 km) is according to my experience best for your piston rings. Having lower oil consumption then that leads to a build up of hard, shiny coal in the piston ring groove. This shiny coal is the nightmare of a piston designer. It leads to cold stuck and later to hot stuck piston rings and to so called ring riding. The hard coal grows behind the piston ring, leading to increased piston ring wear. This coal is so hard, that you can't remove it even with a screwdriver.
It consists of Calcium / Magnesium salts coming from the additive package.