Why is their a difference between the KWCA All Class Rankings and the Individual Class Rankings?

For Example:

Kaiden Powell 4A 120# - 6th ----- All Class Rankings 113# - 6th
Keith Sanders 4A 120# - 3rd ------All Class Rankings 113# - 7th
Brock Sutton 4A 120# - 5th ------All Class Rankings 106# - 7th

Just curious, thanks