During a project, the purpose of examining the cost baseline is to:

Organizing payment of bills is an accounts payable or financial administration function, not the purpose of establishing or examining a cost baseline.

The cost baseline reflects planned costs derived from estimates and the schedule, not the minimum possible cost - cost optimization is a separate exercise from baselining.

The cost baseline aggregates all planned project expenditures into a time-phased budget, allowing the project manager to anticipate total planned costs at any point in the project. It serves as the reference point for earned value management, enabling comparisons between what was planned to spend and what was actually spent. Establishing the cost baseline essentially answers the question - how much do we expect to spend and when?

The cost baseline tracks planned expenditures (outflows only) - comparing against total planned income is a profitability or financial forecasting function, not a cost performance measurement function.