I just got the Imperial Knights codex and I was a little confused on the invincible behemoth rule. It states "any attacks or special abilities that permanently lower the armor value of a target vehicle do not affect a super-heavy walker. Note that attacks or abilities that count the armor value as being lower, but do not actually change it, work normally." First of all what kind of attacks permanently lower the armor value for a vehicle? Secondly, how does the interpretation on lance weapons work? Are they in the second category of the rule?