Information reconciliation is a critical component of Continuous-Variable Quantum Key Distribution (CVQKD) systems. This particular step of the CV-QKD system significantly affects the extraction key rate. Previous studies that incorporate higher-order DM while accounting for the information reconciliation step in the computation of the extraction key rate of CV-QKD systems have focused on multidimensional reconciliation. However, higher-order DM formats, such as 64-QAM, enable higher SNRs where slice reconciliation is known to outperform multidimensional reconciliation. In this work, we compare the performance of multidimensional reconciliation and slice reconciliation in DM-CV-QKD systems. Our findings demonstrate that slice reconciliation delivers superior performance at metropolitan distances. At 20 km, using slice reconciliation with 3 slices of code rates 0, 0.01, and 0.6 increases the key rate by more than 400 times when compared to multidimensional reconciliation with a code rate of 0.05. This significant performance boost more than compensates for the higher computational time associated with slice reconciliation. With the proper optimization of the number of slices, and of the code rate per slice, slice reconciliation is a valid option for real-world implementations of DM-CV-QKD systems using higher-order constellations.