Hmm. I just created that Age exactly as you wrote it in my test world, and it generated with no instability.
As a personal thing, I tend to write the Sun out as Zero Length, Noon, Sun, but I don't think it matters. And specifying Full Length with the Moon is unnecessary, but that definitely doesn't add instability.
Edit: Ok, checked it twice, generated two ages with the pages laid out as you specified, no instability. Check your book, you can turn the pages if you click the bottom right, so double check your logic.
As a personal thing, I tend to write the Sun out as Zero Length, Noon, Sun, but I don't think it matters. And specifying Full Length with the Moon is unnecessary, but that definitely doesn't add instability.
Edit: Ok, checked it twice, generated two ages with the pages laid out as you specified, no instability. Check your book, you can turn the pages if you click the bottom right, so double check your logic.