Hi Lingababe,
Here are the steps to enter your Police Subsistence Pay on SC return:
1. When you are in your return, click on State Taxes, Your State Return, and click on "Continue" for South Carolina.
2. Go through the screens again by clicking on "Continue", until you have reached the page "Here's the income that South Carolina handles differently".
3. Scroll down to the "Public Service" section, and click on "Start" next to Subsistence Allowance.
4. Follow the on-screen directions and enter the number of days.