ME.19:5.1 - Descriptive Stop

This is a constructed design-office history, not a report about a real organization. The office must reconcile names and source editions after drawing signoff differentiated. For this case, independent A.3.1 identification and ME.15 variant qualification have already established common Method M-Signoff-0 and local variants M-Signoff-E and M-Signoff-M. All return approve/reject for a drawing, but the electrical variant requires clearance and harness-revision checks, while the mechanical variant requires load-case and fit checks; each withholds approval when its required check is absent. Those reusable differences are not inferred from separate form names. No professional-family or composite-Method claim is made.

The explanandum is this local differentiation and its documented timing. The receiver needs to distinguish the introduction of the different checks from their later representation in separate electronic forms. It does not need a claim that one pressure caused the split or that either variant is better.

The case premises also admit ElectricalReviewer-E and MechanicalReviewer-M as Agents for their respective checking under A.13, and their 9 and 18 April occurrences WE7 and WM4 as Work under A.15.1. The Work enacts M-Signoff-E and M-Signoff-M, respectively; E1 and M1 are the instructions used, not the enacted Methods. The bounded source set contains these case facts:

Date and source	Recoverable fact and limit
15 January 2024, signoff instruction S3	One common signoff account covers both drawing types and checks that required evidence is present. S3 contains neither variant’s distinct test-and-withhold rule. A source omission alone does not prove that nobody already performed such checks.
4 March, exception log X2; 11 March, proposal P1	X2 records two returned drawings, one lacking an electrical-clearance check and one lacking the mechanical load case. P1 cites these exceptions and proposes the two domain-specific rules. It also retains the alternative of common signoff with expert escalation; the record does not show that the exceptions alone determined the choice.
2 April, approval A14 and instructions E1/M1	A14 approves the two local variants for their respective drawing types. E1 and M1 state the different required checks and failure returns. The common-with-escalation proposal is not selected in A14, but the deliberation minutes are missing.
9 and 18 April, signoff Work WE7/WM4 and their annotated results	ElectricalReviewer-E follows E1 in WE7 and withholds approval for missing clearance evidence; MechanicalReviewer-M follows M1 in WM4 and withholds it for a missing load case. The records support these two enactments before electronic-form separation, not population-wide use or the first-ever occurrences.
6 May, PLM migration note T2 and form edition F2	Separate electronic forms and approval-record names are introduced. T2 says they carry the existing E1/M1 rules. It supplies no new variant semantics and no evidence that the forms caused earlier Work.

Before inspecting the April records, the office has two serious explanations. R-demand says domain-specific omissions prompted the proposal and selection of different rules; it predicts a problem record, a response proposal, and distinct checks before the form migration. R-carrier says the apparent split is only a naming or recording effect of that migration; it predicts unchanged checks beneath the new names. R-carrier is initially plausible because the searchable PLM history starts with F2 and makes the split look like a May event.

Comparing E1/M1 and WE7/WM4 with S3 and T2 is diagnostic: different reusable checks and their enactments are recorded in April, before F2. This contradicts R-carrier’s strong claim that only names changed in May. It fits R-demand, but the available records do not settle why the office selected separate rules over common signoff with escalation, or how other pressures contributed. Missing deliberation evidence leaves that link unresolved here; a separate control office is not a universal requirement for within-case causal inquiry. A weaker carrier contribution to later retention remains possible and untested; rejecting the naming-only account does not prove its rival.

DA-Signoff-Differentiation-1 returns these grades and limits:

Claim	Grade and allowed use
The common and domain-specific instructions differ in the named required checks and stops.	Source-supported by S3/E1/M1; Method identity and variant qualification remain the separate case premises.
Separate rules were approved by 2 April and enacted in the two named April Work occurrences.	Source-supported by A14 and WE7/WM4. This is a documented bound, not an exact origin date or evidence of universal uptake.
The March exceptions were a stated reason for proposing the variants.	Source-supported by P1; that stated reason is not a causal-effect result.
The split was merely a May renaming with no earlier semantic difference.	Contradicted by the April instructions and Work records.
Demand caused selection over common signoff with escalation, or the carrier caused later retention.	Missing causal support; retain the distinct hypotheses and missing deliberation/continuation evidence.

The receiving source-reconciliation decision can now keep E1 and M1 as different variant descriptions, keep S3 as the common predecessor account, and link F2 as their later form without dating Method differentiation from form creation. It leaves the exact first occurrence and reasons for selection unresolved. No C.28 result is created because no causal reliance is taken. Reopen the relevant date, relation, or link claim if an earlier instruction, the missing deliberation record, or contrary Work evidence appears; do not choose today’s architecture from this history alone.