I don't think they ever mention her other anniversaries. Even when she promoted Only One before, they never really showed that it's gonna be her 12th anniversary then. They also didn't have any special promotions on her exact 12th anniversary. The only time they promoted her anniversary was on her 10th anniversary when she released Hurricane Venus. Probably why it sold so much. They promoted it hard back then with streets having banners of her anniversary everywhere. On Only One she had her own TV show solely for her album release. But for her 8th album, she had commercials on Mnet and well a poster on SM's artium. This is probably her worst ever promotion period.
Yes, that's true but even though 12 is a big number it isn't really too special of a number unlike 10 or 15? lol. Maybe I'm just being too hopeful.