I think we should do a little experiment. Upon last check a few weeks ago, the Dahlias I dug and stored were looking good. From past year's experience, I know I'm not out of the woods yet, but almost :-). I'd like to try sending you some divisions of my tubers, and see how they perform for you. After dividing, I'm going to have more than I can plant. I have a feeling you've simply stumbled upon some not so great tubers, I'm sure Dahlias are gonna love your garden.
I'll take another closer look at all my tubers, and make notes of colors and varieties I've got. I'll Cmail the list to you