Retaining CWT fuel
I find the idea of maintaining CWT fuel any longer than is necessary to be less than ideal fuel management practice. Apart from wishing to use fuel, which for any number of reasons may be unable to be transfered at a later stage of the flight, it would seem to me that it would be desireable to maintain fuel in the wing tanks for as long as possible, not least to maintain wing strength and reduce wing loading.
In the unlikely event that CWT pumps are unuseable at a later stage of a flight the fuel in the CWT is about as useful as fuel in the underground storage tanks, a situation which could prove embarassing if both destination and a suitable alternate cannot be reached with the remaining wing tank fuel.