The assessment and collection of late charges for more than a ten-day delinquency, interest, costs or other penalties which may be assessed in connection with a tenant's neglect, failure, delay or refusal to pay rent when it becomes due under the terms of a lease or rental agreement or otherwise to comply with the terms thereof shall not constitute charges in excess of the maximum or ceiling rents; both the applicability of such charges may be contested at law by the tenant. Assessment and collection of a late charge for delinquency of less than 10 days in any rental payment shall be added to the rent charged for the apartment, to determine whether the owner has exceeded the maximum or ceiling rent. Nothing in this section shall inhibit the right of either the owner or the tenant to seek such remedies at law as may be available to him, whether such remedies include a dispossession or other actions at law, it being the intent of this section merely to make a determination as to whether or not an owner is exceeding the maximum or ceiling rents as defined herein.