First of all, you should check to make sure that you are truly supposed to get 11 blocks, even with the elevated activity factor. Most likely you are, but you should check it out to verify. Also, as you check it out, play around with activity factors to see where the "break" is, you may be close enough to the breaking point that you could allow yourself to go to 12 blocks.
Assuming that 11 blocks is what you get, you can divide it up in the way that works for you. Depending on your workout intensity and the proximity to the next meal, you may or may not need a pre or post workout snack. When I work out, it is usually after work and before supper, and its been awhile since lunch, so I will eat a pre-snack. But, since dinner is right around the corner, I generally don't eat the post-snack. I have also divided up meals and snacks to accommodate my workouts, too. That is acceptable to do.
It is really up to you as far as how to divide up your snacks and meals. Just keep the basics in mind and eat again within 4-6 hours of your last meal, eat within an hour of rising, and have your bedtime snack before your bedtime.
By no means should you not have a bedtime snack, unless your dinner meal is close to that point.
And, it is not recommended by the Zone to eat more blocks on exercise days. You should eat the same number of blocks on all days, regardless.
Hope this isn't too confusing!