Mathematical language is not effectively understood by many people. People may possibly mistakenly use "month to month average" when they really want the 'average a month' but that doesn't change the meaning of those conditions, equally as people writing about "stationery cars" does not change the meaning of "stationery" https://financefeeds.com/why-some-brokers-lose-and-others-profit-andreas-kapsos-breaks-it-down/