You didn't misread.
Most of us here are both learning and trying to help others at the same time, so some answers can be a bit confused. Jolteon has mastered this stuff, and really knows what he's talking about.
There's a page
here on RNGing Wonder Cards you might like to check out. It's by Kaphotics, another accomplished RNGer and teacher.
I got the impression, reading your questions, you still don't fully understand the two RNGs, the IV-RNG and the PID-RNG, and the different ways to manipulate each.
To take it back to basics, in gen 5 there is one random number generator for deciding the IVs, the IV-RNG, and another for deciding everything else, the PID-RNG.
Advancing the IV frame is usually done by walking/turning. This also advances the PID frame to an extent which varies depending on many factors. The difficulty in working out exactly how much this has advanced your PID frame is why beginners are advised to use seeds for captures with an IV frame of 1.
Advancing the PID fame is done by saving, or by flipping the summaries of Chatots on which you have recorded a custom chatter.
You asked about sandstorms. You never RNG in a sandstorm. It advances the frame ridiculously. Nor in fog, which prevents you sweet scenting. You get rid of either of these by entering the area, saving, soft resetting, turning your DS's time back a month, re-entering the game and engaging in any random battle. Then save, turn off, enter the time for your seed and get back into the game again. You will have to repeat this for each saved capture you do in the area.