(+) Mill Tolrance value in Input Spreadsheet

The input spreadsheet shows a (+) Mill Tolerance of 0%. This field is not editable in Caesar II for B 31.3 code. The Minimum mill tolerance field under the Computation Control tab of Configure / Setup Menu shows a value of 12.5%. How do I change the value of (+) Mill tolerance in the input spreadsheet to 12.5%? The version of C2 used by me is 4.3. Thanks

The "+Mill Tolerance" field is only used for the TD/12 piping code.