The rule that a 'pinch and a punch' must be implemented before midday was an unofficial addition introduced in 2000 by a large Melbourne community of enthusiasts who sought to make the rules of the custom less flexible. The new 'rule' quickly garnered attention and regard, however, many have opt its inclusion from the official custom.
It is NOT official in any sense and nowadays, is only given practice within local Melbourne communities and by bogans. It is completely understandable that Sydney-siders would have no idea of such silly and bogan-like rules. In fact, it is silly that aside from the fact that it must be implemented on the first day of the month, that a part from that, there are any other rules!