I've discovered the new coreBOS versions always write six decimals to the database, despite the user settings. so € 500,00 always becomes € 500,000000. App stil functions, but it's kind of weird.
We now have up to 6 decimal precision. To support that all numbers are saved with 6 decimals and then shown to each user depending on their preferences. Internally we have to save them all because there could be users seeing that same number with a different amount of decimals.
Thanks. I learned as much from the gitter group. I'm in the process of adjusting my code to use the system native functions to calculation the user's precision.