A provisional increase of the main rent under section 18a MRG is tied to a specific maintenance work and to the landlord’s obligation to carry it out. If the promised works are not carried out, section 18a(2) MRG requires the additional amounts arising from the provisional increase to be refunded with appropriate interest.
The refund analysis therefore starts with the principle decision, the landlord’s undertaking and the actual course of the works. A short delay does not answer the question by itself. The key issue is whether the works named in the decision were commenced and carried out within the reasonable period applicable to the undertaking.