Starting today, AWS Pricing Calculator will enable you to re-access your previously saved estimate with pricing as on the date you created the estimate, while giving you the option to update the estimate to reflect latest pricing. The new experience will now make it possible for you to track changes to your cost estimates over time. When updating your previously saved estimate to reflect latest pricing, you may have to enter inputs for specific services to account for any new changes made to service estimation logic or the underlying pricing model since the creation of the estimate. To help you stay informed on the factors leading to these changes, we are also launching a Service updates page that records any significant updates made to computation logic of services within the calculator.
Source:: Amazon AWS