I have been using that as a deduction for quite some time. 15 years ago I used $2.00 per client. I live in Colorado, but it is a federal return so I don't think what state you are in matters.
If you use an accountant for your return it's always good to inquire with them; however they may not know either. This is what was I was taught as a student in 2000 and them was confirmed by Margo Bowman in continuing Ed courses that I have taken with her.