This is a reasonable supposition, but it's not true. The FCC can and has created a whole raft of specific rules that implement the m much broader Title II requirements as they apply to ISPs, including decisions not to impose certain Title II requirements (which is a power that the statute itself gives them).
If, say, you were an ISP, reading Title I and Title II would tell you very little about what you have to do to comply with the FCC's rules. You would have to read the actual FCC rules and the order to actually understand your legal obligations.
(Maybe you have in mind a quibble about what "rules" are. By "rules" I mean the U.S. government publications that tell you what you have to do in order to not be fined or punished in some other way by the U.S. government, and specifically the FCC.)
> The change being that ISPs are now regulated under Title II rather than Title I.
That is a description of the change. The changes made to Title 47 are how ISP's are actually being regulated under Title II. A translation of what they are saying in the changes to section 8.3 is:
"Because Title II gives us the authority to do so, we choose to regulate them using that authority from Title II by making these specific changes to Title 47."
Again, what you quoted is not part of any CFR. What you quoted is not federal code.
What I quoted is an actual change to federal code which is what actually regulates ISP's "under" the authority given by title II. The actual federal code being changed is: https://www.ecfr.gov/current/title-47/chapter-I/subchapter-B... which has a note that "Title 47 was last amended 4/22/2024." but does not yet show the changes. The most recent version currently available is from changes enacted 12/06/2023. Within the next week or so it will show the changes made by Section X and Appendix A to CFR Title 47 "under" the authority granted by CFR Title II.
That is what it actually means "that ISPs are now regulated under Title II" (as you wrote). Saying "ISPs are now regulated under Title II" is just saying it. Changing Title 47 is actually doing it.
That's it. That's the rule change. Full stop.
If you'd like to understand what's different between Title I and Title II, I suggest checking out the law in question.