Turnkey is an easy word to say. What it means in practice is that when something goes wrong on site — and something always does — it becomes my problem rather than yours.
What it includes
Everything in a complete set of drawings, plus the execution: the local team, the schedule, the suppliers, the site itself. One conversation instead of six.
What it asks of me
Distance means I can't drop by. So the process has to compensate — certified local partners executing what I design, a shared channel that stays open, a report at every stage, decisions documented rather than remembered.
None of that is overhead. It's the reason the model works at all.
What it gives you
You choose things. You don't chase them.
The difference between those two verbs is most of what people are actually paying for.