If the company so desire, all such last-mentioned accommodation works shall be constructed under the superintendence of their engineer, and according to plans and specifications to be submitted to and approved by such engineer nevertheless the company shall not be entitled to require either that plans should be adopted which would involve a greater expence than that incurred in the execution of similar works by the company, or that the plans selected should be executed in a more expensive manner than that adopted in similar cases by the company.