Worn timing guides maybe?
I would think if low oil pressure is affecting the lifters, then the Vanos requiring lots of oil and the cam ledge nearby are not going to be in better shape. I remember reading some owners replaced the lifters and the engine still ticks. That would be because the root cause was not the lifters but the wear in the cam ledges.
Originally this mechanic thought a motor flush would solve the sticking lifters problem. No, it was not the lifters after all.