For a 100mm thick driveway slab, typical mesh size is F62, 72 for 125mm and 82 for 150mm.
However.
Have you increased your mesh size but remained at the same thickness? Eg. do you have 100mm concrete with 72 mesh size?
Obviously, increasing the mesh size willy-nilly is not recommended, but there are no hard rules that I can find. Can I still have 100mm with F72? Will the concrete actually crack easier if thickness is not increased?