Escorted work takes longer and should be priced that way
An escorted attendance is slower than an unescorted one. The crew works at the pace the escort can sustain, cannot split across areas, and loses time at the start and end of each entry. None of that reflects on anybody's performance; it is simply what a controlled environment requires. Pricing it as though it were open access produces an arrangement that either runs over or delivers less than the specification says.
It also affects scheduling. Escorts are usually people with other duties, so the attendance has to fit their availability rather than a cleaning roster. Establishing that at the outset, and naming an alternative contact, prevents a situation where the whole arrangement depends on one person being at work on a particular evening. Escorts are frequently the same people who are needed elsewhere when something goes wrong.
