Changing Giving Levels Best Practice Question

Hello Community! Our Development team has recently upped all of our benefited giving levels. We haven’t changed these in some time. I got a question from the team about how to view historic giving levels AND the current one at the same time, which I don’t have a lot of familiarity with. It looks like changing the giving level matrix in a campaign changing the giving levels for all existing gifts; we are disinclined to make new membership campaigns as we’ve been using the same ones for many years now. The help pages talk about about adding historic giving summaries to the “Giving” tab on a patron account , which isn’t a feature we’ve ever used before. I’m curious if others have changed their donor benefit levels recently and are willing to share how they made those changes in TM. Thanks all!