Doing all repairs on site does offer economic benefits when you consider that if all work is done on site- having a large shop ( and all the related expenses) is not needed.

I have a small shop which is where I do all my subassembly work, but unless the customer requests it, the lift stays at their location.
If a customer requests the lift be moved to the shop- I have access to a larger shop for these purposes. Of course- the related costs of renting the space for the job have to be included in their bill- a fact which keeps moving lifts to the shop to a minimum.

At times such as these, having the economic advantage( ie- less expensive labor rate), comes in handy when companies are checking their options.