I'm still not sure why the files were syncing at a larger size, but here is what I did to work around it. I highlighted Music in MMW, then went to Tools-->Sync Devices-->Send to xxx SD Card. This copied the files at the same size as the MMW library. I then performed a sync, and it matched the files I copied over. This also added my playlists, and left me a library on my phone that matched my computer.

Do you have a lot (large) of Artwork associated with the files? Maybe it's embedding them.

I don't believe I am converting to a lossless format. On my SD auto conversion settings on MMW, the only "Format on Device" set up is MP3. I can't find any format settings in MMA.

Perhaps you're converting format from lossy (like MP3) to lossless (like WAV or FLAC)?

Just set up MMW (version 4.1.21.1873) and MMA Pro. I am performing my first sync, and noticed a few odd things:

1. The file size is much larger on my device (Galaxy S8 with an SD card) than in the MediaMonkey library on my PC. If I click on Music on the left side of MMW, at the bottom it shows 12,604 files, 58.6 GB. If I click on my SD card, it shows audio of 274.0 GB. This was a brand new SD card with nothing on it before I started the sync. In addition, if I look at the Downloading window on my phone, the size of each individual song transferring is about 4x what it is in my MediaMonkey library on my computer. For example, one song in the Downloading window shows a size of 33.2 MB as it syncs. If I click on the same song in the MediaMonkey library, it shows as 8.7 MB. Are these songs really syncing at these larger sizes, or is this some sort of compression issue?

2. The downloading window shows (xxxx/10162) files synced. However, I have 12,604 files in my library. How do I find out which files were not synced, and then get them to sync?