Mr. E. E. Sherer is another Hammelman buddy at the Post Office Department. His name first appears on a handful of Hammelman FDCs for the Victory issue (Scott 537) of 1919.
When compared to the other Hammelman E12 FDCs, this Sherer cover appears to be overpaid by four cents (the block of four). It might be a triple weight cover, but I don’t think so. Hammelman occasionally would use blocks of four as above for no apparent reason. Who knows? There might even be a printing flaw like a double transfer.