What’s the difference between self-archiving allowed under the current Journal Publishing Agreement terms and the ACS AuthorChoice+12 program?

ACS AuthorChoice+12 offers authors the lowest cost option to make the final published article–the version of record--available via open access.  Additional benefits of the ACS AuthorChoice +12 program include (a) the ability to self-archive the version of record/final published article in locations of the author’s choosing after 12 months and (b) ACS Certified Deposit of the version of record in repositories upon request by the author.