Hugs, hun for the nw's. It is sooo hard when you're tired and you also have to work! Can your husband help out? Even on week-ends so you can catch up on sleep?
OK, if independent sleep is the issue and feeding is a prop, then he needs to have some other way to sooth himself to sleep. Does he have a lovey or a special blankie/ teddy, etc? There are different methods you can try to get rid of the feed-to-sleep prop.
the one method that you are doing right now is reducing the amount of formula per bottle over time. In reviewing one of the FAQs, I think you need to do this more gradually so add 2.5 scoops for 3 nights, then drop to 2 scoops for another 3 nights, etc.
How we stopped the night feeds with a 9 month oldThe gentle removal plan is another method to consider. Since you are bottle feeding, this is something that your DH can help out with also.
Gentle Removal Plan