Anyone switch from Experience Beyond to More and keep device promo?

Rep told me I can downgrade from Experience Beyond to Experience More after a few months and still keep the iPhone 17 On Us promo since Experience More also qualifies.

Has anyone actually done this? Is this wrong info?

I don't want to lose the promo if I switch plans down the line. Working through Costco, and I haven't ported my numbers over yet. Any real-world experiences would be helpful. Thanks!