Reading about the new merged CHD set, it appears to rebuild an older set to make the current on requires the older 0145 set, and not the last 0.146 set. With an existing 0.146 CHD set, even when rebuilt into a merged set in CLRMAMEPro, it will only join the new 0.147 CHD merged torrent at 30%. This is still a big chunk of about 68GB off the total size, but very annoying all the same as the complete chd set is 229GB. Very annoying to have to download so much again.