If you delay another half hour, could you still shoot tonight 12 hours after that and be OK with the delay in your shot schedule. You can move shots back 1/2 hour once a day, or 15 minutes a shot. If you can't change your schedule, skip the shot. He will be high tonight, but safe today. If you delay the decision to shoot, you would want his numbers to be up quite a bit.
He's out of the danger zone now, but still on the edge. I would give him a couple tsp,of his regular low carb food and test again in half an hour. He has earned a dose reduction down to 0.75 units when you shoot next.