I sent an email to Hasbro Australia about the Wave 4 PCC 5pks (Steamhammer and Grimstone) since they've only been seen at Toyworlds in one state and they sent me back this reply:

Hi

The combiners you are enquiring about: Wave 4 Assortment of the PowerCore Combiners 5-Packs: "PowerCore Combiners 5-Pack Steamhammer with Constructicons" and "PowerCore Combiners 5-Pack Grimstone with Dinobots have been shipped to Woolworths stores Australia wide.
If this is true then it's awesome news, coz Woolworths sell the 5pks for only $25