Lot size reduction. The Land Use Board, where permitted by §§ 525-9 through § 525-13, may approve a subdivision employing the use of lot size averaging, as defined in this chapter, when the reduction in the size of some lots and the corresponding increase in the size of other lots will result in a more logical development pattern, for reasons which may include site constraints such as wetlands and buffers, floodways, flood fringes and associated buffers, slopes greater than or equal to 15%, rock outcroppings, high seasonal groundwater and shallow depth to bedrock, septic effluent disposal limitations, limited groundwater yield or other physical features. The deed for any lot so created shall contain a restriction against its further subdivision for the purpose of creating an additional lot or lots, except when such further subdivisions would be allowed by amendment to this chapter.