Will iTunes Match re-upload songs replaced in Library at higher bitrate?

Question

In my iTunes Library (18,000+ tracks, mainly ripped from my own CDs), I have tracks ripped at different bitrates, from 128, 160, 256, 320 kbps, as well as Apple Lossless. Given how cheap storage has become since I first ripped many of my CDs, I am going through my CD collection one last time and re-ripping everything into Apple Lossless (ALAC) format. I am starting with the tracks that are in the Library now at 128 & 160 kbps. Many of these songs have been matched by iTunes Match, so they are available to me from iTunes at 256 kbps, but I will still create ALAC versions.
My question is about the tracks that iTunes Match has uploaded to Apple. When I replace the tracks in my Library recorded at low bitrates with the ALAC version, I would like for iTunes Match to notice and re-upload the new file. I understand that iTunes Match will convert ALAC files and upload them at a max of 256 kbps, but right now it seems that iTunes Match does not recognize changes in the underlying file on my computer. For example, if a track was originally uploaded as 128 kbps and then I replace it in my Library with an ALAC version, the 128 kbps version stays on Apple's servers instead of being replaced by a 256 kbps version. I have tested this by downloading tracks from the cloud on other machines connected to my account and they come down at 128 kbps, even though an ALAC file is in the "master" Library.
So my question: is there a way to get iTunes to replace uploaded files on Apple's servers with the highest bitrate version possible if you change the local file after it has been uploaded?
Thanks for any suggestions.
Drew

Answer 1

Hippogreen,
I chose not to follow your Item 4, ie, I am ripping new ALAC tracks directly over the lower bitrate tracks in my existing Library. I just did not want all the extra labor involved in recreating playlists when I reimport, and I did not want to lose the metadata of playcounts, date original imported to library, etc.
If you do as I am doing and want the new ALAC track to directly replace the existing ones in your Library, your Item 1 is relevant:
1) If I have heavily corrected the metadata of a track and it is substantially different from the info provided by iTunes (when I re-rip the CD into ALAC format), how will iTunes know that it is a duplicate?  I assume I will have to manually de-duplicate in such a situation.  I am thinking of uploaded rather than matched tracks.
Like you, I had heavily corrected and personalized metadata, including my preferred capitalizations (often very different from Gracenote and the automated data from iTunes!), track performers, etc. I wanted to preserve all of that, but if your tracks' metadata differs from that which is automatically supplied when you insert a CD, then iTunes will not offer to replace the existing tracks. The solution for me was an AppleScript I found at the fantastic website Doug's AppleScripts for iTunes (dougscripts.com). Get the script "Copy Track Info to CD Tracks v1.3". The URL is:
http://dougscripts.com/itunes/scripts/ss.php?sp=trackinfotocdtracks
This script copies all of your personailzed metadata to the CD tracks so that your own metadata is preserved while iTunes recognizes that the CD is already in your library and replaces the tracks. You can read the complete instructions at dougscripts.com and in the included documentation. It has been a lifesaver, and is truly the only way I have been able to move forward quickly re-ripping my CDs into ALAC.
Note also that when iTunes "replaces" the existing tracks with the new ALAC versions, it does not actually delete the original files. They remain in the same folder where originally stored, but they just become unlinked from the iTunes Library entries. The new files are linked to the iTunes entries, but you are not in danger of losing your original files. You have to go in and delete them manually if you want, or keep them.