Have you temped the meat in several areas? Flat? Point? Temp changes can create wonky end results but a drop down to 230 shouldn't be too troublesome. Remember to rely on probing tender vs temp to determine doneness...especially in the middle of the flat, as points always feel soft and spongy. Push come to shove, you can wrap with peach paper (foil if you lack paper) and hold it in a cooler till later. Let us know how it works out.