If the productivity is fine, go back two days later and check it again. If you're getting more productivity than the national standard, go back and figure the job at a better rate. If a job is taking too long or costing too much, you'll know in time to react. If the job is small, it might be over before you can try to compensate. Otherwise, you might be able to make up on the exterior what you lost on the interior and save the job.
Job costing can go beyond numbers on paper.
If you want to send them in another direction, ask us first. In a three-story renovation job, a general contractor took workers from the first floor to paint a wall on the third floor, and then sent them down to the second floor for awhile, and then back to the first floor. Put a stop to it. Have the guy finish the first floor, then go on to the second floor, and then on to the third. Or if there are priorities, try to make an even transition.