GN 02410.015 Voluntary Tax Withholding (VTW)
4. VTW withholding rates. Only accept a request for the current withholding rates for VTW of 0 percent, 7 percent, 10 percent, 12 percent, or 22 percent only. The IRS sets withholding rates for VTW. Do not input other percentages or flat dollar amounts. For IRS Form W-4V (Voluntary Withholding Request) see GN 02410.017A.