Deductions & credits

If I leave it blank it treats it like a 0 and continues to get the error during Smart Check.  Entering a 1.00 to 0.50 (treated as a 1.00) results in a lowered tax burden (it has an material effect).  If I entered 0.49 to 0.1 it will get treated as if I entered 0 and once again get the error during Smart Check.