Residuals of the measured ¹³C¹⁴N wavenumbers (C. Sneden et al. 2014) of A²Π(v_A = 0 − 22)–X²Σ⁺(v_X = 0−12) transitions (see Table 3) from their theoretical counterparts evaluated: (1) using the original KTPSYT line list (S. V. Kozlov et al. 2024b) and tacitly assuming the mass-invariant properties of the DBOC functions for all states treated (black circles); (2) with the present mass-dependent ab initio DBOC functions determined only for the X and A states (blue circles); and (3) using the mass-dependent semiempirical DBOC functions for all states treated (red circles). The black frame highlights A²Π(v_A = 9)–X²Σ⁺(v_X = 3, 4) bands which undergo strong local perturbations caused by the X²Σ⁺(v_X = 13) state.