Hi Clubbi4.
JLD is right on the money. If you had carpet in the hallway and have replaced it with tiles, then you pay the full price for tiles as cat 1 tiles are in the promotion to only the wet areas so if you upgrade the tiles to 300x600 like we are, then you pay only $60 as that is the difference between cat 1 and whatever cat you're upgrading to.
The standard tile range is $65 per m2. So where ever your getting tiles that aren't in wet areas its $65 per m2 and then the additional upgrade amount, in your case, $60. So in total for your non-standard area you'll be paying $125 per m2.
We have the same promotion as you and we questioned the cost coz we had tiles to the ceiling in the ensuite and because its non-standard we had to pay $125 per m2 for the 300x600 tile. Also to get the brick pattern is an extra cost im pretty sure, but i personally prefer the normal lay out but it comes down to personal choice. Hope this makes sense.. cheers