Tough question.

One thought: If you get a definate diag from the MRI now, you can start treatment now.

Second thought: A problem you have now will still be there (in the MRI) in November. That is not very far away.

Third thought: If you have the MRI now you won't have to get another in November so your question is: Pay 80% now or 80% in November? Can a couple of months make a difference?
What was your first symptoms that led your doc to give you a
"probable MS" diag? Were those symptoms very different from cognitive issues?

My first bad MRI showed lots of lesions in the cognitive area even though I was NOT experiencing anything I would call a cognitive challenge (at the time). Most of my flares are sensory in nature with residual crap like cognitive brain fog on and off...but not really like a flare feeling.

Tell us some more about yourself.....maybe I can help further?