Ebay Labels vs. Auspost Business

Hi there, hoping a more experienced seller might have some advice for me. 

 

Have been selling a few months, doing OK. Sending out about 50-60 parcels / month. 

 

Have been looking into whether I should move all my postage to the Auspost Business account or whether to continue using ebay labels. I know that ebay provides some discounts, but also that Auspost provides bulk discounts. 

 

Have not had time to do the maths yet, has somebody else looked at this issue? Is it better to do the postage through ebay or the Auspost site?