Originally Posted by orbitmic

I fear you are probably right about the time. What do you mean with 'work in general with T5' though? If you mean when the transit option is on and flights are still arriving, then it is absolutely no problem, I have done it many times between any combination of T1, 3, 4, and 5. You don't need to show any travel document to board the transfer bus (makes sense since many people won't have a boarding card yet), and you are dropped at an area where you can go either way to transits or arrivals. Then you go through immigration and customs as you would if you had arrived at T5.