In sidewalk snow removal work we do not perform activities that offer opportunity for positive synergistic effect. In fact, we have the opposite. When we increase the crew size, we lose efficiency. For example; send one person to do a job that takes 4.0 hours of elapsed time (or 4.0 man hours). Now.... send 2 people with the same equipment the same distance to clear the same area, and it takes 2.4 hours of elapsed time (4.8 man hours). The two person crew did it much more quickly (2.4 hours instead of 4.0 hours total), but more time was spent in man-hours and therefore it became less efficient.
Now, in a lot of cases clearing a sidewalk in a little over two hours rather than half a day is a worthwhile tradeoff for the inefficiency - especially if it is snowing like the dickens at the time that the sidewalk needs to be cleared by. The important issue is to recognize that the more people we send to do the job, the faster it is completed - but it is also less efficient in total man-hours spent. Your cost is proportionate to man-hours spent, not elapsed crew time. The small two or three person crew may not effectively clear snow quickly enough at all sized properties.