The project manager could have avoided higher baseline costs by verifying applicable budget inputs related to the project. This involves establishing a baseline that clearly describes the project scope, cost, and schedule1. If deviations from the baseline become necessary, project managers must follow an agreed-upon protocol for communicating issues, determining next steps, and making changes to the plan1. Cost estimation is critical for success in project management because every project manager must estimate all project costs before creating a project budget2. If the project budget is insufficient, it's very likely to face cost overrun2. References:
https://www.projectmanager.com/blog/7-tips-for-preventing-cost-overrun-on-projects
https://training-nyc.com/learn/pmp-certification/baseline