That's probably what I didn't want to hear. It is the same that I experienced and the reason I am regrinding and polishing my crankshaft.
It sounds as if you are losing pressure as the oil heats up and it runs out the worn main and rod bearings. My oil pressure was great when cold. But when hot, at idle it would hover at about 1/2 bar (7 psi) and sometimes go to zero. Give it a little gas (maybe 200 more rpm) and the pressure would go up to 1 bar (14.7 psi) or more.
I drove my car 8 months or more like this. I would always keep the rpms up at idle to make sure I always had sufficient oil pressure. A broken timing chain is forcing me to do a complete overhaul. I'm not sure if the two are related.
The MB spec I guess, is a minimum of .7 bar (10.3 psi) pressure.