The program does not use the floor height you entered in the floor general settings for the irregularity calculation, it calculates an effective floor height by using the geometric heights resulting from the floor levels. The purpose of this is to calculate the irregularity of the floors, which mostly consist of low-level floors, in a near-accurate manner. In this case, the low floors you entered on the ground floor had a slightly decreasing effect on the effective height of the ground floor. It is not necessary to enter the floors as low for the performance calculation, if you want to see the heights you entered in the floor general settings in the report, enter your floors at normal elevation.