So I guess you're saying that dosage doesn't matter (but 12 mg would seem a bit scary to me), but it's the INR that matters to keep it within the target range.
correct the dosage does not matter. Doctors don't grasp this either, so don't feel concerned.
The intention to treat with warfarin is
only INR. No other issue ... just INR.
I know people who take 1.5mg per day, which is a PITA to be honest because adjusting your dose between 1.3 and 1.6mg is not even reliable.
Equally there are people who require 60mg of warfarin per day ...
I have zero conceptual idea as to why anyone thinks taking more is dangerous. I mean if you were taking 1000mg daily (like you would with paracetamol, perhaps even you'd take 2000mg per day as that's just 4 pills) it would still be no more harmful to your body than taking 1000mg of paracetamol.
12 thousandths a a gram ... its not even a grain of salt (and I mean a grain, not the Olde English meaning of a pinch of salt)
Do you drink Alcohol? One "standard" drink is 10g of alcohol (so that's ten thousand milligrams or 10,000mg) ... Alcohol is a known toxin with well known pathways for cellular destruction within the body.
I'm not saying don't drink I'm saying insert some reality about warfarin. (I drank a drink or two a day right up till last year when I got massive tachycardia from it).
I'm wondering where you got your information on warfarin, from "the internet" or a clinician? Either are as likely to know nothing about it. Here at least you are talking with people who have taken warfarin for (in many cases) over 10 years personally.
The arguments against eating a healthy diet are not supported logically nor scientifically. IMO the utter bottom of the science ladder are dieticians. They know enough to be dangerous. They read that Warfarin method of action is a Vitamin K Antagonist (VKA) and so tell you to steer clear of Vitamin K. This does only harm (not even more harm than good).
From
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4998867/
The study has limitations. The main limitation is represented by the small sample size of most studies addressing the interaction between warfarin and dietary vitamin K intake...
... A logical consequence of all these arguments is that the above-reported studies do not support the putative interaction between food and VKA and warrant more appropriate trials to firmly conclude that an interaction between food and VKAs does exist.
so what they are saying in that above study is:
its poorly studied with almost no evidence to support it. Yet clinicians tell people to not eat a healthy diet which has plenty of evidence of harm.
Worse this harm extends to you believing this twaddle and perhaps doubting the (already many) people how have strongly asserted they eat
normally (struck out because the normal US diet is not healthy) a healthy diet filled with greens.