Yes if the route has grass and you are walking outside of the grass the PID frame will be advanced 2 frames every 20 steps.
You're doing 256 steps with 6 Pokemon in your party? I'd think it would be better to do 384 steps with 4 Pokemon in your party so you don't have to go back to the Pokemon center but anyways that's not really important.
Do steps, battle Landorus, catch it immediately (make sure your synchronizer isn't first in your party). If the IVs are correct, check its nature. Check for a match near RNG reporter's "Calculated Initial PIDRNG Frame."
Ok, so 2 frames every 20 steps. I take 256 steps. That should be 24 frame advances for 240 steps right?
I'm repeatedly getting Jolly for my correct seed and Naive for my adjacent seed, but I'm not sure what to do from here.
My correct seed, 67099F71CAD77D00, has an Initial of 51, and Jolly frames are at 64, 65, 83, and 85. My adjacent seed, 6A106BD6DC75CF95, has an initial of 52, with Naive frames at 68, 73, and 99.
None of these are 24 advances. Shouldn't 256 steps advance the frame the same amount regardless of seed?