Fatal Error after little modding WW

[Namikan]

So, I've tried to "mod" WW for personal use.
I wanted to make WW related objects (condoms, birth control pills, etc...), and interactions (such as bikini wax, fertility treatment, etc...) cost a bit more than what it actually does in the original version of the mod, because I think my sims are making money too easily and it'll be a bit more challenging.
I thought it was a rather innocent change to make to WW, as I've done that with all the other mods I use and never got any issue.
But whenever I launch the game with my modified tuning file I get a fatal error, telling me that the package and script files are mismatching. If I take off my modded file and put the original one, the issue is gone, as soon as I replace the original one by mine, the issue is back...
What am I doing wrong?

[TURBODRIVER]

Hey! You shouldn't be modifying the actual WickedWhims package file. Instead take the individual files you want to modify out of the package and put them into a new package. Name the package in such a way that will place it alphabetically before WickedWhims and your modified files in the new package will be loaded first and prioritized. This way you will modify WickedWhims without modifying its actual files.

[Namikan]

2 minutes ago, TURBODRIVER said:

Hey! You shouldn't be modifying the actual WickedWhims package file. Instead take the individual files you want to modify out of the package and put them into a new package. Name the package in such a way that will place it alphabetically before WickedWhims and your modified files in the new package will be loaded first and prioritized. This way you will modify WickedWhims without modifying its actual files.

Thanks a lot for the tip! I'll try this! ?