But where the building consists of more than one distinct and separate units and the standard rent to be determined is that of any particular unit, the formula may present some difficulty of application if it is sought to be applied literally in relation to that particular unit alone and by itself, because even if the reasonable cost of construction of that particular unit can be ascertained, it would not be possible to determine "the market price 1) of the land comprised in the premises on the date of the commencement of construction" since the entire building and not merely that particular unit would be standing on the land and the land on which the building is standing would be land comprised in the building and it would be irrational and absurd to speak of it as land comprised in that particular unit The formula can, however, be applied for determining the standard rent of a particular unit by computing the standard rent of the building ; in accordance with the formula and then apportioning the standard rent so computed amongst the different units of occupation comprised in the building on the basis of floor area, taking into consideration differences, if any, on account of the situation and condition of the various units and the amenities provided in such units.