Tough question. I'm really not sure that my answer will work for you. Hard to think of something inoffensively "office" that turns aggressively "sexy" (for lack of better terms) in the late drydown.
But certainly for that much variation--er, shift between start and finish--and still in the sephora/department store category, I think you'll need to go back to older, classic men's scents. Chanel Pour Monsieur concentree, Chanel's Antaeus, or Caron's Yatagan. Maybe Chanel's Allure, maybe Hermes's Bel Ami or Equipage.
You could always try the signature scent route and declare that your scent is going to mean you, rather than mean an agreement with the time of day, the weather, the season, or they type of event. Then it wouldn't be the scent you'd need to have change from office to evening, it would just be the scent that is you moving between those parts of the day with you. The search for a signature scent is different from the search for one that is office during the day but romantic in the drydown.
I don't know, this is just some fluff that popped into my head I guess. But maybe my recommendations will work for you. Hope so.