Thats right.

bb/100 = PTBB/100 = Poker tracker Big Bets per Hundred hands.

The big bets are from Limit where a big bet is equal to 2 big blinds.

The reason we use PTBB/100 in no limit is because most of us track our results with pokertracker which was originally designed for limit holdem so poker tracker measures winrates with big bets.