Yes. There is no exclusion from income for the payment from an employer to an employee who opts not to take company health coverage. This is so even though you would not have been taxed on the health insurance if you’d opted for it instead of the cash payment.
Advance payment of current tax liability based either on wage withholdings or installment payments of your estimated tax liability. To avoid penalties, you generally must pay to the IRS either 90% of your final tax liability, or either 100% or 110% of the prior year’s tax liability, depending on your adjusted gross income.