s.24-28 LTA54 exclusion (contracting out)

Where a tenancy is outside LTA54 by Order (proper procedure followed) but subsequently some terms and conditions of that tenancy are varied by agreement and incorporated in a Supplemental Lease, I'd appreciate knowing please whether it's necessary for the parties to obtain another Order for the Supplemental Lease or if it could be safely assumed the first Order would extend to include the Supplemental Lease?

I'm under the impression that a Order re contracting-out will only relate to the terms and conditions of the Lease for which that particular Order was obtained, but I may be wrong.