Luck of the draw I think, I've both sent & received packages on time & late, both normal post & express & registered.
Posting before lunch always helps I've found but sometimes I've had stuff sent normal post package & its been quicker than express post, so luck of the draw. I've had parts sent from O/S & it has made it to Australia within a few days, but then once Aus post has got it another week has gone before arriving, they just can't get anything consistant happening.
Recently had a car taillight sent from Wodonga, Vic, by my daughter, normal post pack, sent around lunch on a Wednesday, it was delivered that following Friday to my house in Ballarat around lunch time. The coil I just got was sent registered post last Friday morning, didn't get it until the following Wednesday after 1pm, sent from Bairsdale, Vic.