mate, I can see how it would cause issues, but I reckon you're looking at the wrong end of the system.
If you think you maybe losing power it could well be because there is too much pressure in the crank - increased crank pressure means the pistons are harder to push down on the downward stroke, so I would suspect that more than I would the turbo not spinning as freely.
I can't see that being the case like, but you never know. I think the filter is likely too free flowing for that.
I would have thought the turbo would be having an easier time now it isn't drowning in oil.
I stripped my air intake down a few months back and the amount of oil coating the inside of the plumbing and turbine housing is just unreal.