What "the head commit of the working branch" means? Is it something different from SHA-1 value of the reference in HEAD? If yes, then your sentence is incorrect. If no, then you just saying the same things in some obscure way. Also you say that the "head commit" (whatever it means) points to some SHA-1. That's also something confusing, because commit object itself can contain some pointers to parent commits, but that's not what you meant, right?
Anyway, the sentence is correct as it is, there is nothing to fix in it.