Dear Otto & Co.,
I like Peter's suggestion:
- It might be worthwhile having two participant numbers: one for the full fee paying participants (or equivalent) and one for all participants - use the first in the income and the second in the costs. This may be complicating things too much and I'd be interested in feedback as to whether those numbers differ significantly.
A further feature but further complication, too, would be to add one or more columns which would force the organizer to see what would happen if only a fraction of the hoped-for number of attendees actually appears. This could even be done automatically.
best wishes, Harry