You might be able to use conditional formatting instead of formatting individual cells. I have a pivot table that tracks if deadlines are missed:
![Pivot Formatting](../../I/static/images/91fdf9cff0ccfa09678d34db59f030a9e75edac8c8310e54aa46609378ebcaa2.png)
Select a cell you want to format, go to conditional formatting, and click on "New Rule". Then, you can select which cells you want to format (in my case, the second option), chose your criteria (for me it was if the date is greater than the column next to it on the left), and set your formatting.
My formatting remains regardless of what I add to the table. If you add different columns or cells you want to apply rules to, you'll need to create new formatting rules for those. But, if your columns are fairly consistant, this might do the trick.
Pivot tables format themselves. Any formatting you apply will be lost. I have only been able to consistently apply post formatting using VBA. If you want examples, you will need to post an example of your raw data and your pivot. – OldUgly – 2017-02-10T21:33:35.707