The trick I use is to just use another sheet in excel that is formatted where it looks up a dynamo “overwritten” sheet. I find just data dumping to a formatted excel sheet to be easier to deal with. (I use vba in my excel sheets to pull and push between an import and export sheets for dynamo)
This is usually a good option when using formatted cells. Have one sheet for dumping data and another formatted sheet that reads the data.
To answer your question though, I’m guessing the “clearing” only happens once and then doesn’t run again because there is nothing in that section that updates. You could use something like the Was Run output as the boolean input for Clear Content.