When I recently switched from BMW's 5W-30 fake synthetic to PAO due to visual accumulation of sludge and varnish in the oil filler cap area, I noticed an increase in oil consumption, but also a cleaner engine. Now (after 4 oil changes) the consumption has ceased. Can it be that one can see a rise in oil consumption because the oil is "cleaning" the engine out eg. from neglect or conv. oil deposits before consumption stabilizes?