Contract 6.18.1

The boat note quoted its share against the wrong denominator (feedback #89).

• 6.15.0's note names points / scoring_decks as the rate boat decks contaminate, then reported each member's share against decks_used. On a week that finished those differ: ryguy67 read "1 of 8" where the rate's own denominator makes it 1 of 4 - exactly double. The share is now of scoring_decks, and it reads "up to N", because boat_attacks is the WEEK's counter and the record cannot say which of them fell on a scoring day, so it is a ceiling on the contamination rather than a measurement of it.

Note text only; no field changed.