Sliding scales can work, but it looks like your vet's scale is too radical. There's too much difference between the largest and smallest doses, and the "steps" are too big. Also, by using the scale, you are shooting at bounces. Those high numbers are not "real" in that they have only been caused by the previous dose being too high. You are having to constantly fight against not only the fact that Loki's pancreas is damaged, but also against the "liver panic" that happens automatically every time Loki drops to low numbers. If you have to keep doing that, you'll never be able to reduce his dose, and overall it looks like his doses need to be lowered.
Carl