Federal workers were among the few who were pushed into
deferring their Social Security payroll taxes for the final four months of 2020. Mr. Trump was trying to offer a payroll-tax cut without congressional support, but all he could do under the law was defer the payments. Most employers chose not to change workers’ paychecks at all because of the complexities and potential liability, but Mr. Trump made federal employees participate.
Currently, the workers, including military service members, are required to pay back deferred taxes over the first four months of 2021, and that could pose hardships for people who aren’t expecting smaller paychecks. The congressional agreement
would extend the payback period through December 2021.
So it would be an additional 2ish% the whole year instead of 12ish% the first 4 months. meh