Differentials for high myopia (10 and above)

I am new to the topic and in day 3 of the learning phase. I have extreme myopia R -14 cyl -2,25 L -15,25 cyl 2,25. I am navigating the wiki trying to learn as much as i can and found the mesurment tecnique REALLY cool. i used a rooler and got 6,6cm and 7,1 cm which directly coralates to my accual dioplers of myopia. Now i know its stated to be less accurate with a rooler if u are above -6 but for me it showed my accual prescription. However i am now considering to get differential glasses with -12 and -13 with same ast.

How are things coming along? I’m also started with what I thought was high myopia but not quite like yours.