WD Passport Edge for MAC Warranty Vs. PC

Anybody know why the 500 GB Mac version has a 3 year warranty and the 500GB PC version just a 2 year warranty?  Actually it seems all the Passport for Mac have a 3 year vs. 2 for the PC version.  Is the Mac version built better?

Thanks.

I think they are they have the same built quality, but usually external drives for Mac are a little bit mode expensive. 

Because it’s more expensive and also the design of the drive is custom made for mac.