If two spectra are the same, the chemical composition of the two cpecimen will be the same. What you saw is the difference in strengh of the same component in two spectra, if memory serves me, that are quite natural and hence the lab personal declined to use the term of 'match' in microspectroscopy.
You cannot say the two cups of coke from the same bottle are not the same chemically just because the volume of the coke in the two cupus is not identical. Got it?