The NPT already states that. However, as I already told you previously, the IAEA is a party to the UN Charter and, by treaty, has an obligation to uphold that charter. If the Security Council decides to have Iran suspend enrichment until they are determined to be in compliance, that's within their authority. iow, it's the SC making the demand, a determination that's made according to UN Charter, not NPT or IAEA mandates.
So the IAEA has been given those numbers by Iran and has been allowed to verify them?
Sounds great, except that, as you offer, the Security Council will likely never sanction military action against Iran, meaning that any action would have to be in violation of the Charter you claim we're trying to uphold. It cuts both ways, particularly wrt Israel, who is considered a pariah state among UN members, if not in the US. So we'd have to violate the charter to uphold it, one of those destroy the village to save it deals.
If Iran's numbers didn't hold up to IAEA scrutiny, they'd be screaming bloody murder, and we both know it, rather than voicing "concerns", their version of trolling.
I try to realize that there are two sides to every story, and also try to recognize when we're being propagandized to serve a hidden agenda, in this case, war with Iran. It's being puffed up as a "We don't have any choice!" song & dance, when that's far from true, when war serves the US not at all, but rather the aims of the Netanyahu govt entirely. They'll manipulate us into serving their interests over our own, if possible, and we'd be fools to allow it.
When an Israeli patriot like Meir Dagan offers that the Iranians are rational and his own govt is not, America needs to engage in some serious introspection, understand our own emotional natures, maintain vigilance against being goaded into a war we don't really want against another country that will never pose an existential threat to us or likely even Israel herself. Yet the Netanyahu govt acts as if they are, which is the nature of paranoid delusion.