I have just bought a guidebook for Tre Cime di Laverdo in the Dolomites. I notice that there isn't any consistency between whether UIAA or French grades are stated on each route. For example the Comici route on Cima Grande states UIAA grades whereas the Brandler-Hasse route specifies French grades. Both are trad routes.
Is there a reason why some European guidebooks inconsistently use either system? Does this suggest different style of route?