To admit that the dispensation - as back and forth as the original was (it covered the consummation/nonconsummation issue with a 'perhaps') - means that this one was designed to cover everything; that's pretty close to infallible in this instance. It was requested and delivered to cover the entire issue of Henry wedding Arthur's widow. What Henry now wants is an admission from the Holy Office that they were wrong. That's what he's asking. So, in this case, it's not wrong. The Leviticus issue was covered under the dispensation issued. Henry had no position in this fight once he wed Katherine.