I took an early withdrawal from my retirement plan to pay for my dependent's higher education, am I subject to the additional 10% tax.

The penalty exemption for higher education applies to withdrawals from an IRA account.  It does not apply to retirement plans other than an IRA.  (https://www.irs.gov/taxtopics/tc558.html)

You would need to be able to prove that you had qualified education expenses that were paid in the year you took the withdrawal. The IRS has defined qualified education expenses as

"For purposes of the 10% additional tax, these expenses are tuition, fees, books, supplies, and equipment required for enrollment or attendance at an eligible educational institution. They also include expenses for special needs services incurred by or for special needs students in connection with their enrollment or attendance. In addition, if the student is at least a half-time student, room and board are qualified education expenses."

You must also factor in any financial aid/assistance when determining if your expenses qualify.  You can only use expenses that are greater than the tax free assistance you have received.


See https://www.irs.gov/publications/p970/ch09.html