No...that 10% (0.1 multiplier) is only the "Penalty" applied if box 7 had a code 1 in it.
The 10% you had withheld may have only been a recommended amount, and may have not actually covered your actual income tax on the distribution.
Any pensions/IRA distributions are subject to being tax at whatever marginal tax rate is applied, based on your total income.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
