Adjacent tissue transfer

How would I code this?
A Patient presents to the operating room for excision of 4.5-cm malignant melanoma of the left forearm. A 6-cm x 6-cm rotation flap was created for closure. I think the CPT® is 14301-LT and dx 172.6. Am I correct? Dont you add 4.5 (first defect) and 6x6=36 (second defect) for a total of 40.5 cm? I am so confused!