Also, even though your right hand is gloriously relaxed, add more pressure to make the contact with the strings stickier. It will reduce the finger motion which is needed for these fast passages. I can hear the the hair is losing contact because in this case, the fingers are too flexible!

I've discovered something huge. Elke, you were right about the string crossing. It is almost imperceptible in the video (I think), but after the string crossing, there is a bit of tension in the arm, then when followed by the 4th finger to 2nd finger bit, more tension creeps in, and the whole shoulder then becomes involved. This throws off the timing with the right hand. I had to watch it about a hundred times to see it. Then I remembered feeling it!

So I think I need to do 2 things. #1, as you said, stick with the bowline, and not only the 2 measures, but the three measures coming in, as they are tricky as well, and probably set up their own tension in the bow arm. #2 Bring the left hand in a little more toward the fingerboard so that the 4th finger does not have to 'reach' at all, even as little as it does, because at this tempo, it is disastrous for the timing with the bow hand. For this, yes, I need to play the Schradieck for strengthening of the 4th finger, and strengthening of the hand frame itself. So #2 will take weeks. <Sigh>. But worth it!

Thank you Elke & Christiane for taking the time to look at the videos. You have given me many good points to consider. Elke, your mention of the fingers and the bow getting out of sync w/a third finger that goes down too fast is a huge consideration @ this tempo. It might be giving me that out-of-sync sound I am hearing. I have NOT been doing Schradieck and will try that. And yes, that string crossing over to the G# for one note and back is hard to keep a minimum bow level change. I tried the bow line for that string crossing and it did not feel economized yet. Christiane, I have made a video of my arm. Am I at the right part of the bow? The balance point in the bow causes my arm to be just above square. At the square of the arm, I am a couple of inches above the balance point. I tend to play at the balance point. My teacher askes me to go that couple of inches up, but I seem to feel more comfortable at the balance point. Do you know the implications of this if any? Also, am I using the right amount of bow? Thank you both!

I just went in and made this video after food shopping. No excuse, I know, but boy was this not that great! But this does show what I am naturally capable of on a moment's notice, and does show the arm, which I think is the focus of this new video. :)

Yes, I discovered the same with Shradiek slurred notes - they can be shockingly 'not' rhythmical, which will impact on coordination with the bow..  So back to lower speeds and finger exercises.  I also use the Shradiek exercises for 'speed training', and yes, i have to admit, it is a VERY slow, barely noticeable process.

Dianne, the video doesn't show your bowing arm, and as Elke pointed out already, it's the coordination between bow and fingers, that determines what speed.  It's very obvious, and I'm also very familiar with it, when bow and fingers 'loose' each other, and then there is a frustrating mess. The only way is going back to lower speeds and starting all over.

And yes, you are right, less bow, and using the right place of your bow, will help tremendously.  Flexible bow hold also comes into it, and playing softly may be easier than loudly.  But without a video that shows your arm, it's hard to comment if there is anything to improve.

I know you've done already all the rhythmical speeding exercises, and what Beth suggests for fast playing in the practice course.  So it's just repeating that over and over again and tons and tons of patience!  There will be minute improvements in time.  Some things simply can't be forced!