I've checked that site but it says nothing about multi-storey cages and whether the upper level(s) count so I thought I'd ask here.
Unfortunately it's not my choice, my mum wants them outside
Which is why I'd make sure they got a lot of time in the house away from the weather. Luckily we don't have extreme weather in the UK, and it rarely gets VERY cold or VERY hot. Of course, it's not the ideal but it's out of my hands.