i finally had a chance to read the pokertracker definition and along with the other explanations here, i think i have it straight now. SLA=semi-loose aggressive preflop, P=passive overall aggresion (including preflop aggression). so, what i've learned is, the "A" in SLA is strictly a function of preflop raise percentage and the "P" is a function of (bet+raise/call) overall, on all streets. i was equating them both to the aggression factor calculation.