Can you explain to me this?

27 waves of 3k warriors, just before hits

76k warriors, 24k pike (from your guide, to clear cav)
333 att hero (85 int)

76k warriors, 24k pike
319 att hero (29 int)

76k warriors, 24k pike
315 att hero (27 int)

(All leadership 100)

20k cav left afterwards?

Against a 12, sword/cav/ram combo, according to areocalc should wipe all cav.