«He stated "+1 for some fixes" which is incorrect as it implies that you may not get all of the security fixes for that additional year and only "some" of them.»

Interesting.

The OP's statement was for "upgrades" not security fixes; I read it as 2 years upgrades and 1 for security fixes beyond feature upgrades. The choice of "some" was ambiguous, but "upgrades" is much less ambiguous to me than you seem to consider and not something I'd directly confuse with "security fixes" alone and something that the (+ 1) seemed to directly add "security feature" context to me, despite the ambiguous wording.

Though that still raises the question of if Google properly subsets general (feature) upgrades and security fixes across that 2 + 1 time period. The ambiguous word choice of "some" could be an editorial indication that the OP considers that Google is likely to release some fixes in more general upgrades that don't fall into that (+ 1) time period. As a non-Android user/follower, I have no knowledge in that area and no opinion to offer of my own if that may in fact be the case. I'm also not the OP so I can't express whether or not that was an editorial opinion.

Even if it was an editorial opinion that was expressed, I'm still not convinced it was "disingenuous on purpose", as it may very well be a sincere/candid opinion of the OP. I can only leave that for the OP to comment on.