BSPT generates templates of blendshapes presets that can be shared between different characters.

You can easily create facial expressions by combining multiple blend shapes into presets. Each preset is controled by a single parameter. So it's really easy to include the API in your game script.
You can create different templates with variations using the same expression name, so you can create differences between characters without any line of code, just by changing the template.
Another advantage is that you don't have to deal with the original blendshapes names, you can use your own naming. If two characters don't have the same blend shapes names, you can unify them with two template files (one for each character) using the same presets names.

Different blend modes are available :
Blend, Min, Max, Override.

The tool is really easy to use, you can modify the presets and see the result in the editor.

BSPT doesn't generate new blendshapes to the model, it's a tool for managing existing blendshapes.

Demo - Doc - Forum