Unfortunately, there is no such message to capture. As I understand the quest (I am one smithing level shy), Postie Pete appears when we attempt to enter the house portal if we meet the requirements. He simply doesn't appear while boosting. I'm currently leveling smithing for this quest, but can wait to provide whatever proofs you decide are acceptable. EDIT: I failed to account for the xp reward from King of the Dwarves, which leveled my smithing to 74, and am now unable to attempt boosting for this quest. :( I can, however, confirm that Postie Pete did not appear when boosting.