If you right click on the display and select "View Properties" you will see displayed on the right of the screen the properties of the displayed waveform. You will notice that you have No. samples 405 (2430), this indicates that you have "Sin(x)/x Interpolation" on which expands the 405 actual samples to a displayable 2430 which are the values that will be saved when you save the file. You can turn off Interpolation from Tools->Preferences->Sampling if you wish.
When testing your file I also noticed that when loading the psdata file it shows 405 (25920) samples, which is a bug, although this can be rectified by moving back to buffer 31 and forward again to 32.