Luck is EVERYTHING. So if it's a High Luck day, maybe try 2 more resets? And if that doesn't work, wait for the next High Luck day and try again. I wonder about your Luck as on my only run as deep as Floor 300 I got way more than 13 Treasure Rooms, plus the 6 total Golden Chests.
Go on a High Luck day and use whatever the best Luck Buffs you have, Lucky Lunch really makes a difference for me, I have a Sea Cucumber Pond just to generate a new one every 3 days or so. If your Statue of Blessings also gives you Luck that day, all the better. This is not necessarily for the AutoPetter itself as Luck doesn't affect its chances to appear in the Chests, only to spawn more Treasure Rooms to give you more chances for Mr. Petter to visit.