HR Expense Usability Decimal Precision

I want to be able to have a decimal precision different from the default 'Product Price' precision. But, if I create this new decimal precision via the XML data of the hr_expense_usability module, it won't apply on demo data nor data created via post_install script, because it's too "late" in the module installation process. I tried to create this new decimal precision via a pre_init_hook, but it doesn't work. So I decided to make a small module that only creates this decimal precision and the hr_expense_usability module depends on it.

The typical use case is:

• I want to keep the Product Price precision to 2 (default value)
• I want to have the Expense Unit Price precision to 3 (default value) to have proper support for KM costs (official French KM costs have a decimal precision of 3)