We can determine concentration from absorbance at a particular wavelength as: Absorbance= (absorption co-efficient)x (concentration)x (path length)= - log [Isample/Iblank]. If we measure two different sample solutions at two different wavelengths having same concentration and same path-length but having different absorption co-efficient. Since, the concentration and path-length are same therefore the sample having greater absorption co-efficient must yield greater absorbance. Is there any dependency of absorbance on the instrumental factors such as light source/detector or chemical composition of the sample so that regardless of the absorption co-efficient the sample with lower absorption co-efficient may yield greater absorbance.
Given your stipulations, the answer is no. Make sure you have correctly blanked the instrument at the relevant wavelength for each sample, using the identical solvent containing the analyte in each case.
If you have data that appear to conflict with Adam's response then the samples are non-compliant with the stipulated conditions
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