[Sprint Samsung Galaxy S III] niteglo:
"What makes you think it is using Sprint Towers?"

1. When you flashed it, I was running stock operating system rooted and of course after you flashed it, the PRL you put on it. In the status menu it said Verizon Wireless. Now no matter what rom or PRL combination i've tried (PRLs only used from OP), I'm getting either a non-descript network title like "preferred system" (which I think comes up on the selectel PRL, not sure though) or sprint. There is no indication of Verizon.

2. Speed. Verizon has great 3g speed in my area. Also, they have great 3g speed in Portland, all throughout Washington, Eugene, Florence - just to name a few of the area's that I've tested. I have tested with speedtest, tested streaming, and downloads. It alls caps out at about 20-25k/s which is roughly 20% or less of VZW 3g speed.

3. Signal strengh. I was a Sprint customer for 4 years. They have always had terrible signal strength. I'm going off of the -dbm, not 'bars'. So when I am using the phone in familiar spots and one day I'm getting -90dbm (with high download speeds), and the next day the same location is -110dbm and it doesn't get better... something's up. That's Sprint signal strength in this area. That's also a reflection of Sprint's challenge of their frequency not getting inside buildings as well as verizons. However, it's not a phone issue. Where sprint has great signal, my phone reflects that - I get fantastic coverage in good sprint areas. I get constant connections, no disconnects, etc. Still though, the data speed remains the same. And yes, it does indicate that I'm EVDO rev A8 in the status menu.

So that's why I think it's on sprint constantly. If it were one of those as a stand alone issue then I'd be ready to dismiss the notion, but having all 3 happen simultaneously makes me extremely suspicious. Of course I'm still open to other suggestions.

"When you loaded the new Rom how did you do so?"

I used the latest version of TWRP, wiping system/data/cache 3x before flashing the ROM. I used the recommended stable kernel that everyone was getting good results with. When I restored the nandroid I'd made of the stock OS, I wiped system/data/cache 3x before restoring as well.

"You said all was well until you flashed a Rom and then Nandroid restored back correct?"

Unfortunately, I was experiencing an issue on the stock ROM where the signal bar would stick (the graphic wouldn't update, and it wouldn't update in the status menu) but data connectivity would be fine. I wasn't certain what that was related to. Also, it was taking a while to detect a network when I was in range if it didn't already have signal. Like up to 90s before it would connect. This was mostly manageable, but since I used the phone for work, I flashed 3 of the PRLs from the original topic at various times over 3 hours (using the PRL write mod for the sprint s4), before realizing that the different PRL's didn't affect those issues. I then restored a backup I'd made of the original one you flashed with the phone. The PRL flashing happened in the same time frame as the ROM flashing (not exactly but close). I didn't notice the data speed until the next day because I hadn't done anything data intensive (streaming, downloading, etc)

Taking a look to see if the values changed would be great. I'm certainly not thinking it did it on it's own. I've been very careful to not mess with anything, so it's really a matter of figuring out what I might have done to cause it. Though I don't really know. I tried to get a hold of selectel to see if they could do anything on their end... however, they're not in today because of the holiday (the cell phone department).

I will have time over the next day or two or three if you want to take a look to see if any of the programming settings have changed. I don't know how they would have, but it's certainly possible. I could have inadvertently messed something up through a back-door sort of way.