One document, priced the same way by everyone
A tender is only as good as what you sent out. If three contractors price three different interpretations of the same scheme, the cheapest number usually belongs to whoever missed the most, and you find out about it in month four. A fully measured bill removes that problem. Everyone prices the same quantities, against the same methodology, with the same assumptions stated. What you get back is a genuine comparison rather than a guess, and a benchmark you can hold the winning contractor to for the rest of the job.