THE DIRECTOR APPLIES A SET SCORE
When both NS EW pairs at a table are awarded a set score by the director say a 60:60 result, it means each pair gets a guaranteed 60% of a TOP.
A complete board has
a top of 2(R-1)
a par of (R-1) and
an MP total for each NS and EW side of Rx(R-1)
where R is number of results on the traveller.
The usual method is to first score the board as a short board without the awarded result. The board is then scaled up through the Skewered Movement formula MP x SF +(SF-1) using a scale factor of R/(R-1) where R is the number of results of the full traveller. This leaves an mp gap equivalent to a phantom PAR (50%:50%).
The set scores of 60% TOP are entered on the traveller against the appropriate pairs. The scorer has to live with this board returning slightly more MPs than the others when reconciled to results spreadsheet.
For any set award of 60:40 40:60 60:60 or 40:40 the board is scored short, scaled up, and the set results are then just entered directly on traveller.
It is possible to choose scale factors that leave sufficient match point space for a set score, but there are problems. If a gap of 0.6TOP is required then a shortened board can be scaled up using a SF=(R– 0.2)/(R–1). The gap of 0.4TOP requires a SF= (R+ 0.2)/(R–1). The factors used for the NS/EW sides can be the same or different. The board does present the correct total mps with the set scores included but now the mp scores for opponent NS and EW pairs no longer add across to a TOP or a consistent value. The skewered movement formula is not mathematically designed to ‘scale in’ set scores other than pars, if the NS and EW scores are to remain complementary.