The production refers to the shooting days. This is the point where all those best laid plans are fulfilled. If everything is well prepared there is no reason why this shouldn't go smoothly. However, even the best of plans may have to be slightly modified depending on circumstances. Sometimes, the weather is always a factor in outdoor shoots and if budget allows, more time allocated to shooting should be made if possible to counter this. Most eventualities can be worked round with an experienced team but it is thoroughly recommended that your company key people are either 'on set' or easily contactable on the production days.