Mate you probably shouldn't put $10k into something you don't understand. You're not getting 10% for 12 months. You're getting a 9.62% rate for six months, and then a 6.48% rate for six months, and if you sell at that point then you lose three months of interest.

If I'm doing the math right, then your blended rate after one year including the penalty, for I bonds purchased during the past six months, is about 6.54%.