I think you're right. And that it'd take rather much time & inconvenience, for the customers, to in effect "micro manage" payments for individual features, and

I think you're right. And that it'd take rather much time & inconvenience, for the customers, to in effect "micro manage" payments for individual features, and agree internally about if to spend money on this feature or that feature At the same time, maybe for some rare & "really big" features, it could be worth the extra administrative work, to pay for that particular feature