Without re-saving, FR/LG behave a lot like Emerald. It works better since it seeds using the time spent on the intro, rather than always 0 like Emerald. It gets better if you re-save every now and then, since they save some random numbers to seed from when you save. These could be taken from time played, steps taken, or the current RNG state; I'm not sure exactly. I always walk around and re-save every 25 SRs just to be safe. I've gotten 3 Game Corner prize shinies from unique frames on the same save file this way.