I don't do slow pitch, but USSSA is a bit unique in the base award on a ball thrown to dead ball territory.
See the SLOWPITCH rule copied here:
EFFECT Sec. 7. F. In all cases, when a blocked ball occurs on an overthrown live ball, the ball is immediately dead. Each and every Base Runner is awarded two bases from last base occupied, unless required to retouch.
I believe that the old 1+1 may still be alive in USSSA slow pitch!!!!!
Here is the USSSA rule site :
http://www.usssa.com/usssa/usssa-gen...1204.htm#rule8
Roger Greene