Multiple regional power grids in China have adopted the control performance standard (CPS) to assess the performance of inter-provincial tie-line operations, which has played a significant role in the reduction of both power deviation on inter-provincial tie lines and frequency deviation across the grid. However, in recent years, during peak electricity consumption months, the provinces in recipient regions often face a collective shortage of frequency regulation resources, while inter-provincial electricity spot market prices remain high. The current CPS assessment mechanism, which calculates CPS penalties based on a lower fixed price, has become ineffective as a safe guard for short-term power and frequency balance. Therefore, a master-slave game model between the regional dispatch center and provincial dispatch centers is proposed to determine the CPS assessment price that ensures sufficient reservation of automatic generation control (AGC) adjustable capacity. In this model, the regional dispatch center sets the CPS assessment price, and the provincial dispatch center responds by formulating day-ahead dispatch plan based on this price. The regional dispatch center adjusts the assessment price based on the dispatch optimization results of the provincial center until the adjustable capacity or frequency deviation of the province meets certain requirements. Case study results show that when the assessment price is set at eight times the highest value of various market prices, the assessment mechanism effectively incentivizes provincial dispatch centers to purchase inter-provincial spot electricity and demand response resources in face of generation shortage. This approach enables the system to meet the maximum predicted load and potential forecast errors, thereby maintaining the frequency deviation of the interconnected power grid within acceptable limits.