When a '0' value is XOGed in a Budget Plan, these values as being stored as 'NULL'.
Steps to Reproduce
This is by design. Due to performance reasons, Time Scaled Value doesn't differentiate between '0' (default) and 'NULL' values when a TSV doesn't have at least one non-zero value row.
For both 'NULL' and '0', slicing table won't have any value anyways.