please more explain and whether or not Baker is correct

Abel contracted with Baker Construction, Inc. to erect a metal building as an addition to an existing structure. The two structures were to share a common wall, and the frames and panel heights of the new building were to match those of the existing structure. Shortly before completion of the project, however, it was apparent that the roof line of the new building was approximately 3 inches higher than that of the existing structure. Baker Construction modified the ridge caps of the buildings to blend the roof lines. The discrepancy had other consequences, however, including misalignment of the gutters and windows of the two buildings, which resulted in an icing problem in the winter. Abel occupied the new structure but refused to make the last payment under the contract. Baker Construction asserted a breach of contract claim for the unpaid monies under the contract. In the lawsuit, Baker Construction acknowledged discrepancies between what the contract called for and what occurred during the actual construction but claimed that there had been substantial performance. Explain whether or not Baker is correct