I didn't know about about the volumetric thingy until the incident today...

Usually I just check the rate at Pos Laju website by selecting in the region and weight. As usual, this time I check the rate to send a 1kg item to Sabah from Peninsular is RM11.00, so I quoted the buyer RM11.00 for postage.
When I go and post that time, that fellow said need to use volumetric and the cost is RM35.88! After deducting the super tip profit margin... I need to pay RM 12.00 extra from my own pocket for this trade!

It's a lesson I learn which cost RM 12.00, worth it?