§ 3.8.2 Unless otherwise provided in the Contract Documents,
.1 allowances shall cover the cost to the Contractor of materials and equipment delivered at the site and all required taxes, less applicable trade discounts;
.2 Contractor’s costs for unloading and handling at the site, labor, installation costs, overhead, profit and other expenses contemplated for
stated allowance amounts shall be included in the Contract Sum but not in the allowance; and
.3 whenever costs are more than or less than allowances, the Contract Sum shall be adjusted accordingly by Change Order. The amount of the Change Order shall reflect (1) the difference between actual costs and the allowances under Section 3.8.2.1 and (2) changes in Contractor’s costs under Section 3.8.2.2.
I understand the meaning behind .1 and .2, but I feel confused over the second half of .3
Why would the Change Order include "changes in the contractor's cost" if it already stated that unloading, handling, labor, installation etc should be provided for in the Contract Sum?