Thats rather odd.
Indeed very odd.
The should be using RAT's unitholders' funds to buy back RAT units and REU unitholders' funds to buy back REU units.
There should not be any money where they can be picking and choosing which one is best value.
Of course the Rubicon corporation or AFG could be using its own money to be buying shares in its offshoots, but that is not the same as a buyback and cancellation exercise at all.