§ 78

If the tenant has paid too little in advance contributions according to a consumption account, the landlord may demand additional payment with the first rent payment due one month after the consumption account has been received by the tenant. However, if the additional payment exceeds 3 months' rent, the tenant is entitled to pay in three equal monthly installments, with the first installment due at the set time for the additional payment. If the tenant moves out, the additional payment must be made no later than the moving-out day.

Stk. 2.If the tenant has paid too much in advance contributions according to a consumption account, the excess amount must be refunded to the tenant or deducted from the first rent payment after the consumption account has been received by the tenant.