The cache is not at the posted coordinates.
Punctual, pedantic and perpetually grumpy, The Postman has taken up rounds in Dural. He is not reknowned for friendliness, but he’s infamous for his strange numbering system and even stranger delivery habits. He doesn’t stop at every house only certain ones, according to some pattern known only to him and his new friend. Day after day, he mutters to himself, scribbles a few numbers on scrap paper, and vanishes down the road before anyone can ask questions.
In the last two days, his discarded notes were found in a bin outside a Dural bakery he is known to frequent. One mentioned he’d delivered as far as house number (16,12,17,18,(19-14),18,12,19) and the next day he reached house number (2,(1+16),(8-7),16,(16+4),14,9,13,11) apparently following the same strange function. He didn’t say how many houses he visited, but those numbers hold the key to finding the cache.