These are my thoughts and my experience. When I did my (first) 4th Step, I was only sober a few months. My thinking and my memory were both still quite muddled. The 4th Step that I did was as thorough and honest as I was able to do, at that point in time.
To me, and maybe others don't look at it this way, but to me, the 10th Step is, in part, to clear up new things that come up on a daily basis. However, at other times, something big and old rumbles around under the surface for a while and I'm not even sure what it is, until one day I get this realization that I need to look at something more closely.
For instance, a few months ago, I was a little irritated at my husband, and he (unknowingly) made an expression that reminded me so very much of his father. At that paticular moment, I felt exceptionally poorly toward my husband and realized it was out of proportion to what he had done to irritate me to begin with. Then I realized - it was his resemblance to my father in law that was sticking in my craw.
My father in law was not on my first 4th Step list. We rarely saw him, and although I really did not him at all, I didn't feel that I harbored any resentments toward him. Well, this situation showed me that there is a deep, old dislike and resentment of him (although he had already passed away) and that I needed to take a look at this.
Under the "more will be revealed" category, I found this to be pretty old and pretty big. So the best way for me to go at it was with the columns used in the 4th Step.
Maybe technically it's called a Tenth Step, but since I put pen to paper and use the columns, I call it another 4th Step.
I can only know what I know at any given point in time, and when more is revealed, sometimes it's helpful for me to revisit other Steps in more detail with a different situation in mind.
That's what works for me.