Does the interval of 1 month during rule creation equal to 30 days?

An interval of one month will result in the same date during the previous month and it is not a period of 30 days.

For example: should a rule that would check whether the sum of transactions is above a certain value with a month interval be applied on a transaction that was initiated on the 19th of November, the starting date of calculation for the total amount will be the 19th of October.

With the above example in case the interval is set to 2 months, then the sum would be calculated from the 19th of September.

In case the purchase is made on the 29th, 30th or the 31st of March, the starting date will be 28th (or 29th during leap years) of February.