That's not too bad then...he just wants "fast food" (easily digested) when the weather might turn cold. Very smart actually...good survival instincts.
I've had my share of finicky snakes over the years anyway. My tri-color TX longnose snake (not a natural mouse eater in the wild at all) does well on fuzzy mice all year
except he fasts some over winter months. Very predictable...& same reason as your grey-banded. He loses a little weight in winter & regains it eating like crazy the rest
of the time. He's even tried to "catch" my hand a few times!(hilarious because of his small narrow mouth)