Since I seldom use Spotlight, instead use a find application such as EasyFind (free) and also
use Disk Utility, and Get Info on the Macintosh HD to see what the related unused verses used
capacities of the hard drive status are, usually users of Spotlight among several drives will go
and rebuild the Spotlight Index to help make it work better. One of the results has been to make
the details appear a little more accurately, when they may show a larger proven error in content.
Glad to hear you were able to resolve this issue, and the other provided Support page helped.
Good luck & happy computing!