Section 551.5 - Frequency and other limitations(a) The Postal Service is authorized to issue semipostal stamps for a 10-year period beginning on the date on which semipostal stamps are first sold to the public under 39 U.S.C. 416 . The Office of Stamp Services will determine the date of commencement of the 10-year period.(d) Prior to or after the issuance of a given discretionary semipostal stamp, the Postal Service may withdraw the semipostal stamp from sale, or to reduce the sales period, if, inter alia:(1) Its sales or revenue statistics are lower than expected,(2) The sales or revenue projections are lower than expected, or(3) The cause or recipient executive agency does not further, or does not comply with, the statutory purposes or requirements of the Semipostal Authorization Act. 81 FR 23164 , Apr. 20, 2016, as amended at 85 FR 55193 , Sept. 4, 2020 81 FR 23164 , 4/20/2016; 85 FR 55193 , 10/5/2020