This paper presents a study on innovative Building Information Modelling (BIM) practices for construction cost estimating. By collaborating with a major construction company, I explored the challenges of integrating advanced BIM capabilities into organizational processes. The study validated its findings through a case study on a real project, highlighting their practical significance. While Building Information Modelling (BIM) offers substantial benefits, challenges such as database adaptation, model collision prevention, and alignment with construction methods must be addressed. Additionally, limitations in current BIM software for preliminary design exports and direct quantity take-off must be considered. Transitioning from traditional CAD-based methods to Revit's advanced BIM capabilities, we achieved a 50% reduction in project timelines. This time-saving enabled our QS team to focus on meticulous detail, leading to a 60% enhancement in the quality of shop drawing reviews. Furthermore, the accelerated workflow empowered the team to surpass their monthly targets by an impressive 25%, demonstrating the transformative impact of BIM on QS operations. When the same analyses were performed using Revit at a Level of Detail (LOD) 400 and with the inclusion of approved categories, the estimated costs increased further by 11%. This finding suggests that BIM-based modelling, by capturing greater detail and complexity, can provide more accurate cost estimates compared to traditional methods.