Hi @Janice608 .
You don't have to mark selected dates in your calendar to set discounts. You can do this by adding further discounts to each offer's calendar. On the right side you have a menu: weekly discount, monthly discount, more discounts (there you can set the discount for 2 weeks, 3 weeks, 5 weeks). This action requires that your calendar is blocked from May if no discounts apply from May. Or apply a price increase of the same percentage from May and leave the discounts.
Regards
Marcin