Welcome to the forum! It’s great to share discussions with other folks who enjoy history.
I think I have found the link to the book you have referenced: https://archive.org/details/lifetimesofgener00read
Interesting question. I believe Simcoe was looking to form a Boston-sourced regiment in 1777. That might date it after 1775, and thus make it chronilogically accurate? I checked for pp 40-41 on the Internet Archives site, though there are several versions of the digital document available, and am unsure which one references the same pages you have noted.
I will also reach out to our social media friends and see if anyone might have some insight.
Are you researching work for a book or doing geneological research? Sounds fun!