A system comprises a circuit analysis module configured to analyze a device under test (DUT), the DUT comprising a plurality of latches coupled together in a scan chain. The circuit analysis module analyzes a DUT for sub-circuits within the DUT and identifies a logical description of identified sub-circuits. A don't-care analysis module couples to the circuit analysis module identifies absolute don't-care latches associated with the identified sub-circuits. A sub-circuit exception module couples to the circuit analysis module and selects weighted input values for an identified sub-circuit, based on the identified absolute don't-care latches and the logical description of the identified sub-circuit. The sub-circuit exception module stores the selected weighted input values for the sub-circuit and associates the selected weighted input values with the logical description.