Medical supply costs for transport are very small. The labor overhead costs are overhead. Insurance is included in the estimate.
A plumber charges you $200 to come to your house, it costs the plumber $20 to come to your house. The latter value is what we're discussing here.
If I charge $163 an hour for an electricians time, the cost to my job for one hour without material is between $130-140 depending on who it is. It only costs the plumber $20 if his time is free, which it isn’t.