I'm either missing something or there's a problem

Question

Hi everybody,
I originally signed up for iTunes Match as a way to a) backup my songs, b) upgrade my songs, and c) have access to my music from all of my devices.  With a semi-large collection (12K+) I find myself making different playlists all of the time, but I usually just create them and listen to them at a later time.  Just recently, I wanted to create a playlist for my new, 64 GB 5S, so naturally the best way to do this was on my iMac.  Since, in the past, I have made playlists on my iMac and later downloaded them on my old 4S and/or iPad, I was under the assumption that the changes to playlists were happening in real time - it appears that I am wrong about that.  To explain:
I started out by taking a bunch of other playlists and dropping them into a new playlist (called "iPhone").  This playlist totalled 5,000 (ish) songs which was WAY too much for what I was looking for.  As such, I copied the "iPhone" playlist and named it "iPhone 11-30-2013" and started pairing it down by deleting duplicates and songs/genre's I didn't want on my phone.  I began this process on the iMac (on 11/30) and continued to whittle the list down on 12/3 at night.  On 12/4 I was in my office with some free time and pulled up the playlist on my phone (i.e. it was uploaded/updated to itunes in the cloud/match) to delete a few individual songs and further the process along.  I deleted (probably) 20 songs before I had to get back to work.  When I got home that night, that's when the problems began.
I started updating the playlist again from the iMac (which had the changes I made earlier from work from my iPhone) and completed the process - trimmed the list down to 1800 songs.  I was now ready to download the playlist onto my phone (overnight).  Unforunately, the updated deletions were not showing up on my iPhone.  My assumption was that the iMac was not synching with iTunes Match, went to "Update iTunes Match" and assumed that  selecting this would upload any changes/additions/subtractions to "the cloud", thus making my updated playlist available on my phone.  Instead, when the backup was finished, the playlist reverted back to where it was earlier that night (i.e. with the changes from work, without the changes from that evening) - pretty frustrating.  I repeated the process - I deleted the songs again, and the same thing happened when I updated again. 
For the third try I did the deletions and made a duplicate of the playlist and named it "12/4".  This time, I updated and, while the "12/4" playlist remained intact on the iMac, the "11/30" reverted back again.  I thought this was very weird, but I was happy that the 12/4 one didn't disappear and I moved to my phone to start the download.  Unfortunately, it didn't show up on my phone.  I tried shutting off match on my phone and turning it back on - but nothing. 
Eventually, it showed up this (late) morning and I'm knee deep in (slowly) downloading the songs to my phone.  It looks like (knock on wood) the process is done, but I know that there's got to be some answers to help me understand how to do this easier.
1) Any idea why my iMac was reverting back to old playlists when I was updating to match?
2) Any idea why the new playlist from the Mac took so long to appear on my iPhone?
Thanks for indulging me with this long post.
Cheers!

Answer 1

Since you migrated your old Mac to the new Mac the file paths to the media used in the project may be different if there is a different name given to the new Mac or user account.  It's happened to others.
I suggest you create a new project and located the media files used in the other project and start over.  You can use the old porject to determine where those file were/should be located.
OT