The Enthusiast version limits the Service & Maintenance functionality to 10 VIN numbers. See VINlimit and "How do the Enthusiast and Professional versions differ".
The VIN numbers entered into your VIN-table or VIN-list of your GS-911 interface, are one-time-writable and CANNOT be removed. Our opinion is that once an Enthusiast owns or has owned 10 BMW motorcycles, he/she can afford the upgrade to a Professional version. See FAQ "How do I upgrade to the Professional version?".