i am remodeling my kitchen/dinning room. The dinning room has 3/4 plywood, the kitchen has 3/4" plus 1/2" plywood. I have new 3/4" hardwood flooring for the area. Adding 3/4" flooring in kitchen area without taking out 1/2" plywood will make floor to high for dishwasher and compactor to fit.
There ya go now see how easy that was.
You may have to remove everything down to the floor joists in this case. All you can do is get after it and see what happens. Plan on the worst in this case, anything less will be a reward.