Yes. I've a different opinion.Manufacturer of ambulance manufactures only the vehicle.Once it reaches the hands of hospital they fix the required equipments.Once it is fixed it becomes part of the vehicle.
The cost of the equipment may be more than the cost of the vehicle. But after it is fixed it becomes indivisible part of the vehicle.Moreover the equipment does not increase the life of the vehicle.
In this case, 2 assets (vehicle and equipment) are combined to form an ambulance.Without equipment, vehicle can still run and get patients to hospital.In my opinion it is not compulsory to install any equipment to the vehicle to call it an ambulance.So 15% / 30% rate would apply.