Accurate mass determination is vital across scientific, industrial, and technological applications, serving as the cornerstone of measurement quality and reliability. Hydraulic pressure balances are renowned for their precision and play a pivotal role in pressure generation. However, the influence of OIML weights used as reference on mass determination accuracy remains a complex and often overlooked aspect. This article investigates, whether OIML weights when used as a reference in determining the weight of disk masses, have an effect on the pressure generated in hydraulic pressure balances, and tries to shed light on the subtle relationship between the weight determination of disk masses and measurement uncertainty. In this study, a hydraulic pressure balance with a measuring range of 20-1600 bar was employed, focusing on three distinct scenarios utilizing different OIML weights (E1, E2, and F1) as references for mass determination. The results revealed small differences in reference pressure (ranging from 2 to 10 ppm) due to variations in mass values resulting from different OIML weight classes used as reference. Importantly, these discrepancies remained within acceptable measurement uncertainty limits, especially in high-pressure scenarios. The primary contributor to measurement uncertainty was the pressure distortion coefficient, emphasizing its significance in calibration and measurement processes. This research provides valuable insights into the interplay of accuracy of OIML weights used as reference, mass determination, and measurement uncertainty in hydraulic pressure balances. It highlights the robustness of pressure balances in high-pressure settings and suggests that variations in weight accuracy classes used as reference have minimal impact on measurement accuracy. Future research may extend these findings to low-pressure systems, offering opportunities to refine measurement practices in the field of pressure metrology.