Okay another feeding question

LIAngel

I posted yesterday about whether or not to stick with a 3 hour during the day schedule or see if she'll go 4 hours.   (Thanks to those who responded).  Here is my new question: What happens if I stick with the 3 hour schedule but she doesn't finish the bottle and then wants more an hour later? Do I then feed her again 3 hours from the 1st attempt or 3 hours from when she actually finished the bottle?  For example:

7:00am- 2 1/2 oz (we put 4 oz in the bottle)

8:00- the rest of the 7:00 bottle

So when would the 3 hour mark be for another full bottle?  10 or 11? 

Also when would/should  she be on a more predictable feeding schedule?  She'll be 3 months on the 25th.  I had her on a nice (8, 11, 2, 5, 8pm,) schedule that she set herself, but that fell out the window somehow.  Not sure what happened there.