Matched music is still showing 128kbps when it shows as 'Matched' in iTunes

Within the past few hours I signed up for Music Match. Music match examined the library and matched my music, it shows as matched in iTunes. The music was ripped at 128kbps from my CD's. It syas it is matched but the bit rate is still showing as 128 and not the 256. The files are still on my Mac in the iTunes folder at the lower quality, how can I get the 256kbps music?

Thanks,

HJKeats