It wasn't passing the server validation because of the switched decimal format to using commas.
I resolved this by updating the server validation on line 179 from ",." to ".,".
That makes it get by the number validation, but it still doesn't store the value properly in the database... You may be able to resolve that by changing the number format settings in the database itself. If that doesn't work, then you can do a quick replace to put it back into US number format in the php before doing the database update.