Any account that was part of a recently disabled cross save set up will have a 90 day restriction attached to it that prevents it from participating in a new cross save, whether on the same profile or a different profile. So while you can add that XBox account to this profile with cross save enabled it won't actually be active in the cross save until the 90 day restriction has expired. If you disabled the other cross save today, then the XBox account should be usable in this cross save around July 8th.