There is in fact a simple formula to determine what Pair A is expected to get against Pair B, having missed a board for some reason, based on their percentage score on boards actually played, presumably against a fairly balanced field:
https://en.wikipedia.org/wiki/Log5
Simplified, the score for Pair A against Pair B is ( A x ( 1 - B ) ) / ( ( A x ( 1 - B ) ) + ( B x ( 1 - A ) ) ), A and B being decimal percentages in the range 0 - 1.
So if Mr and Mrs Garbonzo play against Mr and Mrs Haricot and fail to finish the round on time because of a discussion about beans, and the TD determines that both are partly at fault (maybe the men were arguing beanery while the ladies were urging them to fop starting around and continue playing), a fair adjustment would be to use the Log5 formula and compare their final scores on boards played and give an expected result on the board that way. A 60% pair against a 35% pair gets 77.8% by the Log5 formula. The Laws don't allow us to do this, probably because the lawmakers are smart enough to realize that the pairs that use that extra time to get 60% aren't going to be penalized much by the formula and will quickly realize that Log5 is their friend, so there is a compound winkle squeeze out there on every deal and I am taking the time to find it.
In reality, the difference between 40%-50%-60% on a board is usually only a couple of matchpoints, which may be the difference between a place or three, but far more often is not, and arguing that it was the mean director who caused you to be listed a few lines further down in the final rankings, when there were surely countless ways to recover the few matchpoints lost over the course of a session (among them, playing a little faster), is kind of like the time I lost an 32-board IMP League match by 2 IMPs, went to congratulate the other team, and when I returned found that my teammates (who possessed between them vast numbers of university degrees in various applied sciences) were specifically discussing the six boards where there was a two IMP swing the other way, carefully ignoring the handful of deals where 10 or 12 IMPs were on offer had we avoided quite obvious pitfalls....
Plus, a decade or more into the BridgeMates in clubs era, players are finally starting to realize that the arguments that worked in 1977 absolving them of slow play are no longer working when the Director can see on the Round Monitor screen that the Usual Suspects are doing what they usually do. We know who's behind, whether it's N-S or E-W, well before the half-way mark, and we get the pair numbers of the slowest first and match them up with player names later. And usually nod knowingly. It's no use telling us you're blameless by the time we actually decide it's time to say something about it, before the BridgeMate Round Monitor screen becomes an African flag (green: finished the round, red: more than two boards to enter, yellow: on last board).