Feeding less?

The past couple weeks my 3 month old has been slowly spreading out her Feedings more and more. She used to eat every 2 hrs on the dot but when I switched to formula it switched to every 3hrs. She started with about 4 oz. after a week or two of formula she started eating every 4-5 hours but the same amount. Now she will go 5 hours between Feedings except at night she will sleep for 7-8 hours, and she takes about 6oz each feeding, just wondering if anyone else's baby is already spreading out their Feedings to only 4-5 times a day? She's still gaining weight great but sometimes I worry she isn't eating often enough.