We'll put together a proposal, including detailed costings, free of charge.我们将免费拟一份提案，其中包括详细的成本估算。We were asked to prepare detailed costings for the scheme.我们被要求给这个方案作出详细的成本核算。We'll need accurate costings before we can agree to fund the project.在同意投资该方案前，我们需要精确的成本计算。