I've never seen that happen. iTunes loads the data/metadata about the songs and attempts to match them to their database of songs. Then if you were to sign in o

I've never seen that happen. iTunes loads the data/metadata about the songs and attempts to match them to their database of songs. Then if you were to sign in on a different computer with iTunes Match enabled, it would download the songs that it matched from the original computer as a 256kb AAC.