Just to explain the whole power thing a bit further, in the X-Wing series the power you send to the lasers and shields doesn't directly effect how much is available, instead it effects the recharge rate. At neutral power the shields/lasers will remain constant, at increased power they will recharge slowly and at full power they will recharge faster. Likewise, when you set it to decreased power it will slowly de-charge and no power will de-charge faster. If you have reduced the power to the lasers to boost the engine power to help get out of the extremely turbulent air from the sandstorm (trust me, extreme turbulence is not something you want to fly through as a pilot) then its is probable that your lasers will be fully de-charged when you found Dooku's speeder and so in order to get multiple laser shots (it recharges at max power at a rate just a bit slower then you can fire them) you will have to reduce power to the engines for an extended period to store enough charge to get off a decent amount of lasers and compensate for the de-charge rate you'll encounter when you throw power back from the lasers to the engines.
Having said that though, I do agree that it is a pretty stupid line.