I don't feed while my snakes are in shed. The reason i no longer do so, is that feeding in shed caused my one fella to digest verrrry slowly, leaving the prey item bump visible for many days. One reason for a regurgitated meal is that is begins to decompose before it is digested properly.
I wouldn't worry that delaying a meal, or even skipping a meal during shed would cause any real growth setbacks, seeing as in the wild they tend to hide away during these times, and usually don't eat.
IMO, they should be left alone to concentrate their energy on sloughing off a nice complete shed, and can chow down when they are comfortable enough to "hunt" again.