The IDPA rulebook specifies the number of awards to be given at a match.
That's not always practical for all matches. For the 2008 Postal match, for example, the IDPA formula dictated 739 awards!
So there's an option to limit the number of awards in each division/classification.
The quantity options are the same for pre-match and post-match calculations.
The default strictly follows the 2015 rulebook.
If you use the IDPA formula, you can also specify a greater minimum number of awards. (Say, if you want to award 4 awards in each division/classification, even for ones where less than 16 shooters participate.) In this case, check the box as shown and specify the minimum number of awards for each division/classification.
Finally, taking the example of the Postal Match it's possible to arbitrarily limit the maximum number of awards. (Again, you will not be able to specify less than the rulebook minimum of 3.)