That could be a logical FAQ update, yes. :) Can models with Climbing Plus 'hang' onto ceilings the same way then can walls, or are ceilings off-limits to Climbing Plus (and therefore effectively all models)?
Form a sanity perspective I would say no, simply because we would need to determine the interactions of jumping and falling with a model whose base is upside down and then surely some other weird interactions will come up and will be need to be figured out. As I said if players want to house rule it and tackle any weirdness on the spot, they should feel free to do so.
