Each author of SMART software interprets the SMART data differently. IMHO HD Tune is not the best SMART tool, so I would ignore its warnings and interpret them for myself. I prefer HD Sentinel in this regard.
That said, I wouldn't be too concerned if that were my drive, but that's just my opinion.
Here's a case where HD Tune misinterprets Hitachi SMART results:http://www.tomshardware.com/forum/287610-32-reallocation-sector-count
Here are two more bogus warnings:http://i78.photobucket.com/albums/j87/samueltotally/HDDPIO2.jpg
In the previous example, attributes 0A and B8 are perfectly OK (normalised value = 100, raw value = 0). I believe HD Tune's warning is triggered because the Current and Threshold values are "too close".