If you're not calibrating with the skipping method, then yes, it is normal to not find any groupings. After all, the groupings only apply to the skipping method :/
anyways, as for advice, pick a frame (once you find your groupings) that's preferably under 10k, but even better if its under 5k. the shorter the reset, the better chance you have of hitting your target. this is because you'll be able to pull off more resets in the same amount of time if you'd chosen a higher target frame :)
otherwise, I wish you luck (you'll need it!)