You are asking a child to have the "adult" understanding... many of us (in theory adults) do not get "ideal" numbers either. The numbers per se are not the real issue, past a basic point.
Have you let HER tell you how you can help her? MIght take a couple days for the entire conversation.... Im going to ask you on Sunday for a bunch of ways anybody can help you with anything diabetic...
Then when Sunday comes around... ask her. Your list should have some generic, real kid friendly stuff... want to go to a sleep over... want to eat a piece of chocolate cake... want to XYZ...
I'm betting if your list is general (addressing your deeper concerns subtlely) with a couple of razor sharp questions tossed in... suspect you might get the discussion you actually want...
Have you attempted to RADICALLY change you channel? Do something/something(s) so different it makes her jaw drop, and do a double take? Stuff her full of cake, or ice cream, or soda, and do NOTHING to address it diabetes wise??? Obviously you will play catch up on the back end of the game, but may get/hold her attention if simply as mom, you took her out, and pretended nothing special was happening.
Would that radical change in approach make her receptive to a woman to woman talk?!?!
Has your daughter ever met the WOMAN, who also is her mommy, and learned about some of the stupid mistakes you have made? We all make them... it how we become adults.
I'm a fan of the "diabetic vacation" idea, look up the term. Essentially for 72 hours someone does everything she should be doing by the book diabetes-wise. No discussion, no debate, just it is done for us so the "burden" is no longer ours for a brief time. At the end of that time, then you have the chat(s).
Another approach would be what I call "matching". Every test she takes you match her one for one. Now you have no need to do the actual test itself, the goal is whomever getting the blood drops. If you want her to do 6x/day then that is what whomever does as well.
Makes for very informed discussion at the end of that week! The asking for tests is a different creature than having done what she does, is being asked to do... once you have done it yourself.
Ever used one of her syringes, (sic. a bunch of times)? No insulin, just putting the needle into your body, and then pulling it out. Try that game for a week.
If the OLD conversations are not working, the consequence(s) are not getting the result, time to change the blessed channel!!!
When she is taking the tests are you CERTAIN, her fingers are clean? Not talking alcohol swabs, nor hot water even, simply basic clean, so that when she picked up your cinnamon toast this morning, the residue did not effect her reading???
It is entirely possible as well, the formula(s) being used are no longer a) right, b) were never right perhaps. Its a math problem, no emotions involved, just basic math. Your goal is to get a lower result. Dont care what approach, method, bribery works, as long as you get there, right?
Tried the barter system? X readings gets X points regardless of results. Get a certain number of points and she can... ? Could work too.
On a "good day" our blood sugar is a three year old WAITING, begging to throw a tantrum. Somedays it does, and you keep going. Its the habit of such tantrums we need to crush. Which tool/approach do you plan to use???