What happens when you combine multi-speed mail and reduced delivery days? CHAOS!

Multi-speed mail is a senders choice concept whereby the sender pays for a corresponding delivery timeframe.

Reduced delivery days is a concept whereby mail simply isn't delivered on selected days. The non-delivery days would be nominated by Australia Post not the recipient. Also, it is likely non-delivery days would be based on geographic location and therefore unbeknown to the sender, the service they paid for may not be honoured within the expected timeframe. It's like a bad lottery.

The two concepts are not compatible with eachother and you cannot use trend data from multi-speed mail to justify changes in delivery days.

The video below shows computer simulation of what happens when mail is reduced to 3 days a week for a recipient: