2.4.21-pre7, disk size, display wrong or serious bug?

Yesterday I installed an external RAID system, machine was running kernel 2.2.20 and everything worked ok:
~snip~
SCSI device sdb: hdwr sector= 512 bytes. Sectors=1278558208 [624296 MB] [624.3 GB]
~snip~

Then I compiled 2.4.21-pre7 using the old sym53c8xx driver:
~snip~
SCSI device sdb: 1278558208 512-byte hdwr sectors (-444889 MB)
~snip~

and then again using the new sym53c8xx-2 driver:
~snip~
SCSI device sdb: 1278558208 512-byte hdwr sectors (-444889 MB)
~snip~

The system *seems* to work ok but I don't know if it really *does* - I didn't want to experiment very much because the RAID array contains sensitive data and pulling the files back from tape takes forever. Unfortunately kernel 2.4.x will become a must in the near future for this system ... Is it just the display of the value that is wrong or is this something I should really worry about?

I don't want to flood this list so I put complete dmesg output for all three kernel variants on a website in case somebody want's to have a look at it:
http://www.schachtziege.de/sym53c8xx.html

Thank you,
Regards,
Andreas