iPhone 11 promotion with transferred number

I recently bought a new iPhone 11 through Xfinity Mobile and activated a new line with number transferred, which is required for get the $250 prepaid card promotion. But now I want to swap the sim card in new iphone with another existing phone under my Xfinity Mobile account, will doing that cause me to loose the prepaid card? As far as I understand, the promotion doesn't specifically say the new line is bound to the new iphone, so technically, as long as I'm keeping the new line active and in good standing, I should be fine? @CCKenF @ComcastChrisL