To put the "extending their supplies in context":
LAFORGE: With the engines idling, the energy loss has been limited, but our reserves will be depleted in less than three hours. We won't be able to hold our shields in place.
After the "extending of supplies" shields were no longer a problem.
PICARD: Well done, Mister La Forge.
RIKER: Geordi, can you give us enough power to get us out of here?
LAFORGE: Sorry, Commander, we haven't addressed that one yet. First priority was to maintain the shields.
Basically, rather than finding ways to conserve their energy reserves they found ways to use more of it... which apparently makes more energy reserves