How much to feed

I feel like I'm not feeding my LO enough. He's 7 weeks old & formula fed. I give him 4 ounces every 3.5-4 hours. But about a half hour before it's time to eat he gets really fussy, cries & doesn't calm back down until he's fed.

I read to feed daily based on weight x 2.5. He weighs 9.5 pounds, so according to that I'm doing it right. Is it okay to feed him more?

Thanks for the input! I'm a FTM & I get nervous about trying new things with/for my son.