Why would you need a Deck Extension? The Deck Extension is used to fill spaces between 54"-60 inches. A Standard Tub lengths is about 60 inches. The Escape is 50" long and built to easily install into existing tub framing. Yet, often a Deck Extension piece in needed to avoid additional framing.
Buy the DECK EXTENSION and save MONEY. Using the deck extension is MUCH less expensive than re-framing, and re-drywalling!