19 Tex. Admin. Code § 22.296
If the parent is employed on less than a full-time basis, the value of the exemption is to be prorated in accordance with the parent's employment load. Under no circumstances, however, is the exemption to be for an amount less than 25 percent of the student's tuition.
Source Note:The provisions of this §22.296 adopted to be effective November 28, 2005, 30 TexReg 7872.