I'm not sure you are going to get a tidy 12/12, sorry to break it to you! The thing is her pancreas appears to be sputtering, so when that happens from what I have seen if they hit good nadirs they will tend to get duration past +12. If they don't get good nadirs they are shootable at +12, but the tradeoff there is no good nadir. There are times when that is acceptable, but with her ketone history I think you need to go for the good nadirs and live with the late shots.
The only other thing I can think of is to try one of the Ls b/c then you can still shoot on a lower #, in fact with them I think you have to stick pretty tightly to 12/12. I would stick with PZI for now though if you can (why mess with an insulin change that could set you back, when she is doing well).
You are doing really well with the late shots, and I think there is still hope that her pancreas will take over altogether. The more you can keep her in the 50 - 80 range, the more that promotes pancreas healing.
Great that she is feeling better, that is AWESOME news.