I would replace the 4 oz of pale chocolate with 2 oz chocolate and 2 oz of base malt. This way your gravity won't suffer the reduction in malt.
Pale chocolate is fun in a brew, but having 12 oz sitting in the basement waiting for the next recipe may not be worth mail ordering. Depends on how often you brew and how many recipes with pale chocolate malt catch your eye.
So many beers, so little time.