On a thread about LTE a long time ago, the discussion about the relation between loss of NR (due overpitching) and torque increase (added to the loss of NR on the TR) emerged and someone, I think Nick Lappos, explained why it occurs.
In basic terms it's because for any given weight a fixed power will be required to hover (in identical conditions), and as power is a measure of 'rate of work done' it basically means Power = Torque x Nr, with Torque being the 'work' and Nr being the 'rate'. One goes up or down, the other goes down or up.
Reviewing you post and trying to understand, another question arised: if the helicopter is on ground, the amount of thrust generated by the MR shouldn't be related just to the power/pitch/torque (collective position...) applied instead of torque and takeoff weight?
Not sure I follow what you are saying here, but the MR thrust at MPOG will not be affected by the aircraft weight at all.