Deductions & credits

If Line 1a is adjusted, then line 18 is adjusted. If line 1a is not adjusted, then line 18 is not adjusted.

 

From page 9 of the instructions, line 1a would be adjusted unless you qualify for the exception. By default, TT will not make any adjustments unless they are mandatory. You can override TT but that might require using the downloaded version using forms mode.