No matter how many times I read it, I can't interpret it the way you're suggesting. "x soars after y" always reads as "x increases a lot because of y". I don't really get what you're saying.
Are you maybe saying that "soars" might mean "get better", so "failing grades soar" might mean there are actually less failing grades? That's not how I've ever understood that word.
Are you maybe saying that "soars" might mean "get better", so "failing grades soar" might mean there are actually less failing grades? That's not how I've ever understood that word.