Exact transfer without a runtime win

This overview explains how D8 carried a frozen rewrite package to Linux while separating output agreement from profitability. Correct outputs and rule incidence can reproduce even when overhead-inclusive timing reverses direction on another host. Use the verified distributive identity with the same variable meanings on both hosts. Keep the source and candidate identities fixed. Exact matching and equal outputs can transfer even when the performance result does not. On fictional host A, matching costs two and execution costs four, totaling six. The matching control costs eight. Under this declared boundary, the candidate is cheaper. On fictional host B, matching costs five while execution remains four. The total is nine against eight, reversing the result without changing the mathematical answer. These teaching values explain the mechanism and are not the retained D8 timings. D8 carries a frozen one-pass rewrite package to Linux. Exact outputs and rule incidence can reproduce even if overhead-inclusive timing changes direction. They are separate result columns. Use a conceptual rewrite with matching, execution and delivery on one timeline. In this illustration, the same transformation and admitted cases run on the second host. Both hosts have matching outputs and application counts, while their total charged times differ. This shows how exact engineering success can coexist with an unprofitable whole request. The retained D8 comparison reversed the Windows profitability direction on Linux, and unconditional one-pass rewriting was not promoted. That is a result of the frozen experiment, not a reason to hide the second machine or retune the criterion after seeing it. Exact behavior and runtime transfer are separate checks. A system can preserve every decision across hosts while losing its cost advantage because overhead changed. If a threshold is edited after seeing the unfavorable result, the new rule is a new candidate. The old result should remain visible. Editing a parameter cannot turn the already observed frozen test into an unseen successful confirmation. The revision can enter a new development and validation process with appropriate fresh evidence. Keep its identity and scope distinct from the original host-transfer result, including any retained regressions and non-promotion decision. Report exactness and profitability as separate gates. Preserve the Linux loss and use the admitted control unless a justified successor meets the conditions.