Three independent ledgers

This is a residual-response test, not a statement that the entire code is recoverable from $B$. Compare the corresponding distinction in En04-A CheungEn04A.

Neither register count nor a chosen temperature-like label is a mass observable. The isometry condition only requires

It does not force monotone residual dimension. After a physical dilation of readout is included, apparatus outputs may remain in the complete residual even while a scheduled source core becomes smaller.

The finite schedule constructs no black-hole Hamiltonian, continuous backreaction, mass-loss differential equation, or evaporation channel. An externally attached temperature or mass schedule remains an input. Shrinking a named register is not a theorem that a gravitational area shrinks.