I believe it has to do with your sysparamData Converted relationship. I dont think it is working the way that you imagine.
Put a copy of the related CHARGE2_DAYS field on the layout for database.
Most likely it will not be returning a value. Keep in mind that unless specified using GetNthRecord, or using a portal, it will only look at the first related child record.
Therefore Get ( CurrentDate ) - ( a related record which is empty ) = Current DAte.