[JSWolf]

What I am saying is that APNX generation is a feature of Calibre. You can create a column to put in a number you want to use for the final page number.

1. Create a custom numeric column
2 Preferences > Plugin
3. Search for Kindle and select Kindle 2/3/4/Touch/PaperWhite /Voyage Device Interface (1.0.0)
4. Click Customize plugin
5. Check "Send page number information when sending books"
6. Under that select accurate
7. Under "Custom column name to retrieve page counts from" put in the name of the column you created
8. Check "Overwrite existing apnx on device"
9. Click OK
10. Click Apply
11. Click Close

Now, if you do not put in a page number in the custom column, Calibre will still create a page number file for your eBook.

P.S. KF8 is the proper name for AZW3.