Different brands of farro can cook differently. Also, some people like a softer texture and some like a firmer texture. You might also notice different cooking methods - some recipes have a shorter cooking time but longer release time and some recipes (like this one) have a longer cooking time and quick release. For this recipe, I give a range of cooking times (8 to 10 minutes for pearled; 12 to 15 minutes for whole grain.) It's best to error in the side of undercooking slightly. You can always re-seal the lid and program a few more minutes of cooking time if the farro is too chewy for your liking.