X15 efficiency advice

[Nero]

I got my truck done! No issues!

My friend asked me to do a regin on his isx today.
His crankcase pressure was 5.0 inH2O at a idle.
I was told it should be under 1.0 at a idle.
He had black smoke and soot coming out of exaust pipe during the regin. His Crankcase pressure was also up to 7.0 at 1100 rpms during regin.
He said its not burning oil nor loosing collant.
He just changed his crankcase filter. He did have blowby coming out of dipstick and oil fill.

As for as crankcase pressure what levels are ok and how much before it sets off a fault?