A PPC Question for someone, what numbers does the Amazon’s Campaign Manager UI show? If the Campaign is old, is it showing you the ENTIRE history of the campaign combined?

When you decide to either bid higher/lower or even turn off a keyword, do you go by the last 1-2 month performance through the PPC Reports or do you go by the lifetime numbers on Amazon’s website?

My basic question is how useful are the numbers displayed on Amazon’s website, especially with old campaigns?

Thanks in advance! 8)