OD_11.5 is the first major empirical convergence paper of the Obligation Density Programme. Using ABS Census homelessness cube data, AIHW homelessness reporting, and published administrative classifications, the paper identifies seven Obligation Density signatures within the Australian homelessness apparatus. Key findings include: National Hidden Liability Layer (NHLL) ratios between 0.706 and 0.833 across four Census cycles (2006, 2011, 2016, 2021); persistent CNOS threshold sensitivity producing 48–70% headline uplift under a one-bedroom classification shift; strong Indigenous concentration within the hidden housing layer (4.8 times population share in OPGP 7; 6.4 times in NT NHLL rate); 16,552 children under twelve classified by the apparatus as not homeless while living in dwellings requiring three additional bedrooms under the Canadian National Occupancy Standard in 2021; persistent-homelessness growth of 39% across the 2018–2025 window; and instrument-level admissions regarding variables the apparatus cannot witness, including the verbatim AIHW statement that the Specialist Homelessness Services Collection “cannot be used to measure” the principal upstream variable. The paper argues that homelessness is not an isolated social category but the realised tail of a broader obligation-density distribution whose signatures are already present within the apparatus’s own published data. The empirical anchor is the ABS Data Cube 20490DO001_2021.xlsx Table 1.2. Programme function: Empirical surface and public demonstration of the witness architecture. Core structural question: What does obligation-density failure look like once it becomes visible to public measurement systems?