If your last round ends with is taller stitch (e,g, double crochet), consider working a few half double crochet, then a few single crochet, and finally a slip stitch to gradually decrease the height before performing the invisible fasten off. This will create a smoother edge....
The steps in the “invisible decrease” method is more like the steps you take to make a single crochet stitch, compared to the steps you do in a traditional decrease. The invisible decrease would look more like a single crochet and that is why it is more invisible. You can try the ...