The followers metric is not easy to accurately tally. It comes from a query of all your defined relays, so depending on connectivity, it could be inaccurate. Nostr.band maintains a somewhat current tally, but even that isn't always 100% correct, and clients don't necessarily pull that data from nostr.band. Amethyst, for example, does their own relay query, which doesn't happen unless you're viewing your profile. And it takes a while to fully calculate. If you want to use YakiHonne, I think you need to contact them and ask them where, exactly, they're getting that data from, and how often it's updated.