You can select the lump-sum election method if it lowers the taxable portion of your benefits.
Under this method you refigure the taxable part of all your benefits for the earlier year using that year’s income.
Then you subtract any taxable benefits for that year that you previously reported.
The remainder is the taxable part of the lump sum payment.
There are worksheets in Publication 915, Social Security and Equivalent Railroad Retirement Benefits, to help you calculate the taxable portion using this method.