History shows you'd lose the promo and it would be $45.
In addition, from the SAVE24 details:
"For purposes of clarity, any service plan change of any kind - whether initiated by the member or if required by Visible, including but not limited to changes from the Visible plan to the Visible+ plan and vice versa - will result in the discount being removed."
If you have eSIM capability on one of the phones, you might want to try the 15 day free trial for a couple days before deciding. For all intents and purposes, the trial is the Visible base plan. Just use a throw away email for the trial. The SAVE24 promo ends in a few days.
