Any ford
Any forced induction engine is hard on oil. The compressed air gets heated and absorbs moisture. The engine on boost uses more fuel. The extra fuel, compressed air and moisture create blow by. The oil gets contaminated with fuel and moisture, through the pcv. The oil goes through the hot turbo to cool it. This combination can't tolerate long drain intervals.
I'm a little confused about your explination. Here is my understanding; moisture comes from humidity in the air. This makes the air less dense which results in less compression less blow by because of less compression, it also results in less oxygen in the combustion cycle and less ability to burn fuel. At the same temperature and altitude engines make more power in the dry air.
The Positive Crankcase (cc) Vent valve function is to prevent pressurization of the cc to prevent oil leaking out shaft seals and through valve seals on intake stroke. It vents "blow by" from the cc to the intake so it does not pollute the atmosphere like old vents to atmosphere. It draws a vacuum on the cc and it has a check function which when functioning only allows flow out of the crankcase so it can't contaminate the oil unless it is not functioning.
IMO the most significant problem with oil is overheating which causes carbonization turns the oil black is solid and does not lubricate but increases friction. Turbos are hot and are tough on oil because they are hot.
BTW I think I was discussing oil wastage or consumption in the oil level discussion.
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