Regarding the necessity of using different products:
Both Bell Hammer Light and Bell Hammer Seven are high-performance oil additives that form a strong lubricating film on metal surfaces, reducing engine wear and improving quietness.
They share many core performance features, so your reasoning—“Couldn’t I just use one of them across both vehicles?”—is quite logical and reasonable.
That said, it’s also true that each product has been fine-tuned to suit different oil environments and usage conditions.
For example:
Bell Hammer Light is designed to work well with higher viscosity oils such as 10W-40 and is versatile across a wide range of vehicles.
Bell Hammer Seven is optimized for lower viscosity oils like 0W-20, and for hybrid vehicles where fuel efficiency and quiet operation are key.
In short, while both products can be expected to deliver beneficial effects, choosing the one that matches your vehicle’s characteristics will help you get the most out of its intended performance.