It depends on the developers process of coming up with the estimates. If they're breaking down the tasks, thinking of all the things that can go wrong and facto

It depends on the developers process of coming up with the estimates. If they're breaking down the tasks, thinking of all the things that can go wrong and factoring in contingencies, sequencing them understanding dependencies, and work other than delivering code, data migrations, support, monitoring, and so on, the estimate could be thrown out without anyone ever looking at it but the developers would have a much better understanding of the project and a good sketch of a plan of attack to make the time making the estimate all worthwhile.