The applicability of the new depth-atomic absorption relationship to measurements of optical properties of an alkali metal in a non-uniform multi-component combustion flame was numerically studied. The relationship describes the equality between the ratio of the optical depths at far to near wing wavelengths and that of the atomic absorption coefficients at the respective wavelengths. An introduction of biases into theoretical wing intensities and the evaluation of the ratio of the atomic absorption coefficients with far wing temperatures are essential features in the formalism. It is shown that the relationship has sufficient sensitivities to the change of optical quantities to be measured under realistic flame pressures, temperatures and wing spectral levels when the two wavelengths are adequately separated.