Mecretired:
I'll answer what I can.
First -- about your insurance company -- perhaps if you take your request further up the chain and explain that you can only get blood from one arm, and the lab tests probably cost MORE than home testing, you may be able to make some headway. Having an MD who can actually complain to the insurance company may also help.
In my experience, if you're taking a higher dose on two days a week than on the other days, your INR WILL be different on some days than on others. As I noted, on some days, my INR is around 2.7, and on other days (depending on when I take my larger dose), it's more like 3.2 or 3.3. Both values are within range, and I don't make many changes to my dosing. However, I have to wonder if cutting back from 51 mg/week to 49 mg/week will result in any measurable changes -- will I stay around 2.7 every day I test, or will this 2.7 drop because I've stopped taking 8 mg on Thursday and Sunday?
In response to your question about the day of testing -- I think that it probably DOES matter what day you test -- a test on Monday or Tuesday will probably NOT show the effect of the higher Tuesday and Thursday dose -- if you test on Friday, you'll probably see a higher INR.
I also question the wisdom of taking the higher dose only two days apart - rather than trying to spread the difference out -- perhaps Tuesday and Friday or, like I do, Thursday and Sunday. If they want you to have a weekly dose of 57.5, they could probably have you take 8 mg daily (two 4 mg pills) and 9 mg on Thursday (one 4 and one 5), and perhaps 8.5 on Sunday (two 4 and one half of a 1 mg). Actually, 57 is probably close enough (you may not see much benefit from the .5 mg dose). This way, it probably WON'T matter much which day you test because you'll be taking practically the same dosage every day. It may cost a bit more to take two pills a day, rather than one - but generic warfarin is pretty cheap, and jumping from a dime a day to 20 cents a day may be worth it if it lets you get better control of your INR.
Good luck with the insurance company.
(Because I don't have insurance, I wound up buying my meter. I got my meter(s) on eBay and have had no problems with it (them). For some reason, the prices on eBay seem to have increased over the past month or so but with a prescription you may be able to buy a meter from an authorized dealer and take the expense off your taxes if your insurance continues to resist self-testing. There are many of us here who home test, and I know that a few of us own, rather than rent, their meters. It's something that you should consider if you can afford the meter and strips. I personally now use, and favor, my InRatio over my ProTime and ProTime 3 meters, and would not buy a CoaguChek S (although an XS would be fine) )