For the purposes of this section, premises shall be deemed to be used for a more profitable purpose if, but not unless, the rent which the landlord could obtain for the premises if used for that purpose would be greater than the rent which could be obtained if they were used for the purpose of the trade or business carried on by the tenant.
Where an offer of the renewal of a tenancy by the landlord under this section is accepted by the tenant, the rent fixed by the tribunal shall be the rent which in the opinion of the tribunal a willing lessee other than the tenant would agree to give and a willing lessor would agree to accept for the premises having regard to the terms of the lease, but irrespective of the value of any goodwill which may have become attached to the premises by reason of the tenant or his predecessors in title having carried on thereat a particular trade or business.
In the absence of agreement between the parties, all questions as to the right to compensation under this section, and as to the amount thereof, shall be determined by the tribunal.