This can be confusing so let's analyze the following example:
A sample policy condition is the following:
Total Cost ($) increased by more than 20 % over 7 days.
In this example, CloudHealth will evaluate between the last full day of evaluation which is generally 2 days prior to the current date (day X) and 7 days before (day Y). The platform then checks if there was an increase of 20% or more from day Y to day X.