I dunno Eags, I’ve never practiced it as hard as you are doing! 
To be honest, after hitting two or maybe three putts with the dowel rod, my ball striking on the greens always improves so I no longer keep doing it. It’d be interesting to see whether extended drilling using it makes a major difference. I look forward to your report!
By the way, another great drill (that you need a partener to do) is where your friend rolls the ball towards you and you hit it back to him before it stops. Again, just a couple of these drills sees my ballstriking on th egreen improve noticeably.
