Ditto from me. Bias cut on WOF could work because there is a little bit of wiggle room in it, in other words, it is a bit stretchy. If your original bias was cut on Straight of Grain, then you will fight it every minute and have a lot of wrinkles in it. You won't like it. If in doubt, find something that is rounded or make a practice piece using a really long stitch, called a basting stitch. Turn the piece so that you are working with the curve and pin your binding to it. Don't sew, just pin. Can you work it to your satisfaction? If so, then go for it with the oval. If the binding is wrinkling, either change out your binding, or forget the oval.
Happy Quilting!
Edited to add: Forgot to add, after trying the old binding on the practice piece, just unpin the binding, take out the basting stitch, iron the fabric, and you are back to before the test. No fabric lost.