Hi Dan,
Although the peak of Porcine Isophane is between 6-12 hours, it is till very active for up to 16 hours before it tails off, and gone by 24 hours according to the profile chart. Also neutral can start working from 1/2 hour from taking it, and tails off between 4-6 hours. I've always taken profile charts with a pinch of salt, for the simple reason that everyone is different and they are only a guide. You had gr8 control on Lantus and Levemir, but mine on Lantus was erratic and unpredictable, likewise many people on Levemir find it doesn't last 24 hours and split the dose. As I said, I had enourmous probs with hypos on Actrapid, and looking at my profiile chart the profile is very similar to Porcine Neutral which doesn't cause me such problems. Certainly not what I expected and as a result it took a few months for me to pluck up the courage to change to it.
I was using the insulins section of Diabetes UK's Balance supplement "Balance guide to testing & treating diabetes", is that the one you've got?
Jus