Finis Neptune player -- How does it choose the track order?

Short version: How does the Finis Neptune MP3 Player choose the order of the tracks? Long version: I recently bought the Finis Neptune MP3 player. It is an amazing device, but I'm struggling to make it useful for me. The problem is that it seems to play tracks in an arbitrary order. For instance, if I uploadTrack 1 Track 2 Track 3 Track 4 Track 5 It might instead playTrack 4 Track 2 Track 5 Track 1 Track 3 The play order is not random -- it is based on some logic I haven't figured out yet. If I can figure out the logic it uses to choose the track order, I believe I can get the tracks to play in the order I want. I've confirmed that the player does not play tracks in the order of the file names (e.g. "AB3.mp3" doesn't necessarily play before "XYZ.mp3"). Also, I've confirmed that the player does not respect the order specified by Windows Media Player (e.g. if I make an ordered playlist in Media Player, then synchronize it to the Neptune, the order is not preserved). I can't find any mention of this in the user manual or on the Finis website. I'm hopeful that someone in the swim community has already figured it out. If so, please share your experience with me: What logic does the Finis Neptune use to choose the track order? -TC P.S. This is the first MP3 player I've ever owned. I suspect that maybe the answer is obvious to anyone who grew up with Ipods in their ears, but that my lack of experience with such devices prevents me from seeing it.