How are monthly expenses are calculated?

All monthly expenses are unique expenses. Monthly expenses are calculated proportionally to the dates you select. 

For example, an email expense for November is $100. If you select November 1st to November 15 the total days would be 15. So the proportionate monthly expense would be (100/30 days) * 15 days. Leading to a proportionate expense for November 1st to November 15th of $50 dollars.