Combo fed baby drinking less formula

Due to a big delay in my milk coming in and low supply, my 8 week old has been combo fed from his first week. Our routine is breastfeeding approx. 15 min per side then offering a bottle of formula and/or pumped breastmilk if one is available. In the last week I've noticed that he's been drinking less formula - we're down to 6-8oz/day. Could this mean I'm producing more milk now? 🤞🤞🤞 I pump 3x/day after feeding and still only get 3/4 to 2 oz - no change there.

(He hasn't been weighed in the last 2 weeks, so I don't know if he's still gaining weight, but his wet and dirty diapers haven't changed.)