Numerology doesn't have a governing body. There's no equivalent of a periodic table that fixes, once and for all, how the birth number and destiny number should be weighted against each other — which leaves the question open to whoever's teaching the class.
That's not unique to numerology. Plenty of interpretive traditions — astrology's disagreements over which house dominates a chart, tarot's disagreements over reversed-card meaning — run on the same kind of internal debate, unresolved because there's nothing external to check the answer against.
What's genuinely useful here isn't picking a winner. It's understanding what each side of the argument is actually claiming, so you can recognize which tradition a given source is drawing from.
