You need to calibrate frame for Red Gyarados.
Actually, I went back again and reread posts by Romsstar and Expert Evan regarding Red Gyarados, and it seems the problem isn't that the spreads aren't always listed on the correct frame (as mentioned on the first page), but that the nature and IV spread might not match up. However, those posts were from long before the latest version of RNG Reporter.
I just caught my RNG-abused Red Gyarados: Adamant 29/31/29/2/31/31 in a Dive Ball. So for future reference, here's what I did:
1. First I found out my SID with the Chain to SID feature by catching Red Gyarados, calculating its IVs, reset, repeat, until the SID was found.
2. In the Time Finder, I searched for spreads with the IVs I wanted under Method K (but didn't specify nature, synch, or ability). I copied whatever seeds had IV spreads I wanted on reasonable frames, regardless of nature.
3. Using the Chained Shiny (theoretical) search function, I input my ID and SID then pasted each seed in. I kept copying and pasting seeds from the Time Finder until the IV spread came up with an Adamant nature.
4. I saved directly in front of Gyarados, facing it, and noted the locations of my roamers.
5. Copied the seed to Seed to Time, used PikaTimer to hit my seed, advanced frames, caught Gyarados, then checked what frame I landed on. With all roamers free, I could tell if I hit my target seed quickly. At Lake of Rage the frame was anywhere from 5 to 10 frames advanced by the time I brought up the menu. What was cool was that by using Elm Results I could see what frame I started on. What sucked was that as soon as the menu was closed the frame could advance 1-3 before engaging Gyarados. So basically I had to keep trying, always at least 1 frame short of the target, until I finally hit the right frame.
I didn't use a Synchronizer because I wasn't sure how that would affect the RNG. I noticed that Gyarados moves before the menu can be brought up on some seeds, so if that happens on a particular seed I think that re-saving in front of it could help.