Then I switch to every 5-6 hrs. As the formula is thickened and the amount of food is increased, the time between feedings lengthens. From this time to weaning, the maximum amount of formula I feed is 8 cc. More than this will stretch the crop too much and the food will stay in the crop too long, leaving open the possibility of sour crop or Candide. I don't get too concerned if there is a little bit of food left in the crop at feeding time.
Lovebirds seem to do quite well as long as the crop empties at least once a day.
Make sure you discard any unused formula after each feeding. Even if stored in a refrigerator, it's a breeding ground for bacteria. At this time, I disinfect my syringes. You may find that the disinfecting will cause the plunger of the syringe to 'stick,' thus making the syringe a little hard to use. When the baby shows an interest in picking, I transfer it to a small weaning cage.