Rename your tables to a different name but keep the directory the same name. for instance:
Original:
Code:
- main_units_tables <-Keep this the same
- main_units <-Rename this
Change to:
Code:
- main_units_tables
- Alexmcm13_main_units <-any name will do, I just put your name in front
If you leave the file the same name in your mod it will overwrite the default file, if you rename it however it will only overwrite matching rows and keep the remaining vanilla data intact (If that makes any sense). This does not work if your pack file is in movie mode, it works only in mod mode I believe.