In which case, why is it an open book contract? If the specification is that precice, the best fit is usually a fixed price contract. Typically open-book cont

In which case, why is it an open book contract? If the specification is that precice, the best fit is usually a fixed price contract. Typically open-book contracts is to account for uncertainty / flexibility / changes without having to raise endless CRs/WOs. Those fixed price contracts can still have gainshare mechanisms to identify joint cost saving.