Mathematical language is not really perfectly understood by many people. People could mistakenly use "every month average" when they really want the 'average per 30 days' but that doesn't change the meaning of those phrases, equally as people writing about "stationery automobiles" does not change the meaning of "stationery" https://financefeeds.com/the-biggest-threat-to-bitcoin-is-cardano-says-cardano-founder-experts-believe-it-might-be-this-copyright-instead/