The SoftRAID driver always creates the correct parity information for each block when writing to the volume. The parity information gets written out at the same time that your files are written so it should always be correct.
There are problems with specific Macs which can result in this parity information not being written out correctly. If you want to confirm that all the parity information in your RAID 4 or RAID 5 volume is correct, you can validate your volume. When you validate a RAID 4 or RAID 5 volume, SoftRAID reads each set of blocks and calculates its parity information. It then compares this parity information with what is already stored on the volumes disks. If the parity information does not match, it updates the parity information on the disk. The SoftRAID application displays a count of the number of blocks updated whenever you validate a volume.