Copfag here. Had some thoughts on a possible double meaning for the numbers [+21] [+2] [+4].
A common decryption method using modular addition is modulo 26 where letters A - Z get assigned a numeric value. Often A=0, B=1, C=2 and so on. Usually this is used to add a cipher text and encrypted message together to produce the decrypted answer.
If you take just the numeric value assuming A=0 and add the numbers you get the letters VCE.
Digging on those letters produced a company VCE (Virtual Computing Environment) that deals in prepackaged data solutions (racks/servers/storage/etc) they call VBlocks.
They landed a big contract with Facebook back in 2012 as described in the following article: https://www.itprotoday.com/storage/emc-news-facebook-vce-greenplum
I might be onto something or possibly just retarded.