Currently, the spell check prompts the user to change "40s" to "40's." However, just as you would not use an apostrophe in the spelling of "forties," it is not appropriate to use one with digits, in any circumstance (shortened decades use an apostrophe before the numbers: "In the '90s"). MTs could easily trust the spell check on this suggestion, but it is incorrect.
Unfortunately, the incorrect entries are not part of the Nuance dictionaries, but are in the published dictionaries InScribe uses in addition to our own, and we are unable to remove the incorrect entries without removing the entire dictionary.
As a workaround we can force our spell check program to skip words that include numerals. To do this, access the Spelling and Typing options:
Select the option to ignore words that have numerals. This setting will not check the words 40s, 40's, or '40s.
This will allow the spell check to skip over words with numerals, but it will also skip incorrectly spelled words with numerals.