There are other questions that beg asking about this whole thing.
None are directed at the OP or the responses given so far.
I sit here, safely retired after a long career flying helicopters in various regimes around the World.
Someone please tell me why the "Safety Pilot" in the scenario's given cannot "Log" the flight time whilst he is handling the flight controls of the aircraft?
You can Log every minute of it.
The Authorities may not allow it to be applied to any Legal Requirement for Licensing, Currency, or whatever.....but he can indeed Log it.
Why the angst over the Single Pilot/Multi-Pilot certification issue.....why not question the mere fact there is such a distinction to begin with?
If you can fly the machine as a single pilot....you darn tooting can fly the machine with two pilots in the cockpit....so why do the authorities add that requirement on your license.
That should be an Operator SOP issue....not a license issue.
Liability.....is the PIC's burden....not the Safety Pilot.