As for the original question: I think it's fine to have "obvious" derivations included in boQwI', though with a note along the lines of "this wasn't used in a sentence, it's just extrapolated from words we already know". boQwI' is used by a lot of beginners, who might not be aware of the underlying vocabulary patterns that led to getting roSqa'tej from roSqa'QeD, so if they saw the former in the wild they might be confused.