My question is about whether this is on the estimates. As Mr. Oliphant pointed out, some chairs are lenient in this regard, but they do not have to be. If someone objects to a question because it's not strictly on the estimates, then the chair would have to make a ruling.
I'm not sure what the intention is here. Is it going to be open ended? Well, let's make it open ended and not call it just on the estimates. That way you can ask questions on the estimates and anything else, because if you call it on the estimates then you're relying on the goodwill of the chair, and I have no reason to doubt goodwill, but chairs also have to follow the rules if someone calls upon them to do so.