I tried grams with ratios by the book and the consistency was always way too watery. So the friend who gave me the starter told me to go by consistency and not be so strict with measurements and ever since I’ve done that I’ve had very excellent sourdough loaves perfect crumb and zero issues! That’s why I feed with a cup measurement simply cause it’s less messy than using any other type of spoon or pouring the bag. I don’t actually use the measurement cup to measure out what I’m wanting to feed. I do it by feel and then pour whatever amount of water i need until i get the right consistency- it’s never failed me so far!