By the way, as I understand it, the date was never pinned down. One was mentioned by Lefebvre--but only by way of indicating that it was ludicrous, that nothing of the sort was really intended. That's why he mentions just after this the request for still more dossiers, etc. He knew they were giving the appearance of movement--he had been through it all before. It was a runaround.
Basically, you accuse Ratzinger and the Pope of dishonesty with Msgr. Lefebvre for very little reason, if any. There is no reason to think that Ratzinger was lying about the August 15th date, which he told to Msgr. Lefebvre. The idea that Msgr. Lefebvre had been through it before is ridiculous - the Protocol was the first time Rome had agreed to the consecration of a bishop, and previous negotiations were inconclusive because of Msgr. Lefebvre's intransigence against orthodox teaching like religious liberty.