Stone answers that in his dialogue. Enterprise is on priority one.
STONE: Maintenance Section Eighteen. The section is working on the Intrepid. Reschedule. The Enterprise is on priority one.
The reason for priority one is unknown, but that apparently means either Section 18 is additional manpower to existing section(s) working on the Enterprise or the Enterprise just settled into orbit and was waiting for a starbase section to be assigned to her. Intrepid just got short-changed.
Robert Comsol wrote:
But that still doesn't answer the question why Commodore Stone is pulling section 18 from the (unfinished) repair work on the Intrepid and diverts it to work on the Enterprise.
Section 18 may be a specialized repair unit to finish the remaining 13% repairs on the Enterprise but wouldn't they have work sheets and plans for that in the 23rd Century?
Stone is a former Starship commander and now he has to move the repair crews to their next assignment because without his order, they'd just be sitting around?