I always count mine as 3. There's a local bakery I tend to get a roll from at lunch sometimes, they're the crusty (hard on the outside) kind. It's a guessing game sometimes.
I always take 3 for a roll, I've figured it out many times, the only time a roll figured to 5 was at 5 guys burgers and fries, I don't know why, but using their nutrional info, that's how it worked out.