Blackstrap molasses vs regular molasses

I’m aware of how molasses and refined sugar are made from sugar cane and how brown sugar is white sugar with molasses added back to it.

But — how "different" are the three grades of molasses (light, dark, and blackstrap) when they can be used together with sugar?

I understand light molasses have more sugar than dark or blackstrap. But does that simply mean that light molasses is exactly the same as "white sugar + dark molasses" ? And likewise, dark molasses is identical to "white sugar + blackstrap molasses" ?

I’m curious if I can simply just use blackstrap molasses only and just add however much white/refined sugar as needed (to balance out), rather than having to specifically use "light" or "dark" molasses (especially in things that might get blended, where everything is going to get very "well-mixed" anyway!).