I can't imagine "just once" for anything! (Especially if it's good!) I don't do well with one's!
The 12 Steps are referred to in the BB, as a "tool-kit". A tool is most often something that's used -- more than once.
I first used the 12 Steps because of my alcohol-ism. They worked so well -- that I began to use them on all the other areas of my life.
The purpose of Step 10 is "to continue"... to do what we did in Step 4 through Step 9.
A spiritual awakening is a spiritual transformation. I can have an awakening on Monday -- simply observing my life -- I need rest. And, I need sleep. It's part of the living process. But, if I have my awakening on Monday -- and sleep for the rest of my life -- why awaken on Monday? Stay sleeping!
Step 10 is like "Wake up on Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday, ad-infinitum." And, wake up not just once each day -- but after each nap or each dozing off -- during the day.
In the 12 & 12, Bill, refers to Steps 1 through 9, prepares us -- for daily living. When I have a problem show up that I'm unable to solve -- I apply the entire 12 Steps on that individual problem. Guess what? They work!