BL1 BL2 are in sync with PP1 and PP2 they represent the last race and the next to last race -
pp1 is horses' running position in last race 1st call
pp2 is horses' running position in next to last race 1st call
BL1 is lengths off the pace 1st call last race
BL2 is lengths off the pace 1st call next to last race.
https://www.pace-view.net/directions...r-instructions
