Not that you or I metabolize the drug the same, but I'm on 7.5mg 5 days a week and 5mg 2 days a week. My diet isn't a diet. I eat when I can and whatever I want. At this dose, I usually test in the higher 3's. The one week I didn't eat for crap, I tested at 5.2.
I think your answers are
1. Recovery-Your becoming much more active.
2. You may be eating something with hidden Vit K and not know it. Do you do any energy drinks, Carnation Instant Breakfasts, Boost, Ensure, or anything like that?
For the first couple of months, it seems like all you do is chase the numbers around and then suddenly pop, it's in range and stays pretty much there.
The only thing that bothers me with what they're doing with you is the loading dose. They should just do as Marty said and increase the dose, in your case, 15% and spread it out over 7 days rather then one large dose and follow with the norm. See where this next test puts you and if it's still botched, try the 10% solution.
I think I asked you before, but if you can talk to your Cardiologist and see if he knows where you can go to get fingersticks instead of venipuncture, I think you'd be better off. I know the lab I was going to had mine so screwed up that I'm convinced veinous draws aren't all that accurate. I showed them on a chart how they had me at a dose that worked and then a test that was high resulting in lowering the dose and then testing low, then elevating the dose etc,. It always came right back to the same dose which is what I take now. I'm now going to a fingerstick clinic and my results are very consistent compared to the nightmare I was going through before.
Just some ideas to think about.