no starch and carbs after 4 is fine if you are on a "normal" schedule. The reason most folks stay away from carbs in the evening is so theyare all processed before bedtime. With your later schedule you could probabaly have carbs later in the day since you are still active after most folks have gone to bed.

What was your bedtime before the shift change?

What is it now than you work til 11:30?

Find the difference and add that to 4:00 and you should be ok.