The premise is flawed. Extra AP credits (even 5s) are not going to get the student admitted. If they were so important for admission, colleges would insist on receiving those scores directly from the College Board before admission offers are sent out. Instead, students are allowed to self-report their scores.
On the other hand, a few extra AP credits may be a cushion once admitted. Example: the student gets sick with mono or the flu and drops a class or two. The extra AP credits may help allow him or her to still graduate on time.