ITC as an organization has not overruled that in their own
FAQ or otherwise mandated any exceptions to this
FAQ:
Q: If a unit declares a charge against an enemy unit that is entirely on the upper level of a terrain feature such as a ruin, Sector Mechanicus structure, etc., but it cannot physically end its charge move within 1" of any models from that unit (either because there is not enough room to place the charging unit, or because the charging unit is unable to end its move on the upper levels of that terrain feature because of the expanded terrain rules for it – as with ruins, for example), does that charge fail?
A: Yes.
Keep in mind that if it does not have Fly the following applies:
Change the first paragraph of rules text to read:
‘Unless they can Fly, Vehicles, Monsters, Cavalry and Bikers can only be set up or end their move on the ground floor of ruins.’
That having been said . . . it seems to be becoming more common for ITC event organizers (as opposed to ITC itself) to institute house rules around this particular
FAQ so I would check with the
TO in advance if this makes a big difference for your army.