In a word, yes. This is ok. I can’t tell you why self taught fiddlers want to reduce the amount of bow available to them but I have observed many old timey fiddlers do things for weird reasons and then, a trend gets started. It is my belief that much of the fiddling styles we see today are a result of grandpa’s just making tunes easier to play because of his arthritis. I don’t think this is a good reason to modify a classical bow grip or hand position. I also want to say, before I could advise you to move the bow grip up about 1/4 of the bow, I’d want to have a good reason. I’d ask why. Michael is classically trained by has a lot of fiddling experience, so maybe he has a good answer as to why this should be done. A quick google would probably bring a legit answer too.
Meanwhile, I live in a mountain rural area and even the classically trained young students move their bow grips up the stick for fiddling. I could see that maybe bringing the hand closer to the body would make the simple shuffle bowing often employed in fiddling a lot easier. But it does limit the scope of playing so it is not advisable to always play the bow this way.
Sometimes, just for fun, I have students play with bow grip 1/2 way up the stick. I also sometimes have them play with the bow upside down. 🙂 But there are always reasons. And the reasons always go beyond the fun we’re having in the moment. So always maintain your good bow grip no matter where it goes on the stick 🙂