How else would you define there to be only two winning numbers then? If you define the winning number afterwards, there’s no way telling how many numbers of those would’ve been in circulation.
Perhaps they should have instructed the manufacturers to not include numbers which were multiples of, say, 15, but to use all other numbers uniformly.
Random audits (with expensive penalties) could have detected whether the manufacturers had complied with this, without making it too obvious to contestants that the winning number would be a multiple of 15.
The winning bottles could then be manufactured to contain some specific multiple of 15, while still allowing the organisers some freedom to choose which one.
