Navaleye,
1) It was a surprisingly cheap upgrade, if truth be told.
2) The Jags were not used primarily because using them in Afghanistan would have made it much more difficult to get rid of them. Compare: "We're getting rid of the Jaguar early, we haven't deployed it to Afghanistan" with "We're getting rid of Jaguar early even though it proved to be a decisively useful tool in Afghanistan...."
3) After extensive examination and trials the Jag Force themselves judged that they could have operated from Kandahar on a 45° day, with a small but useful warload.
4) The Tornado force is manning two op deployments in the Middle East.