I thought it also meant how many bonus Hi/Lo LEDs were lit before you started playing so if you exchange in with 3 pogo lights lit then you automatically get a bonus.
Quite handy when you have two matching symbols lit either Hi, Hi or Lo,Lo because the first gamble is like 95% guranteed so you can go against the numbers to acheive a slow down bonus.

I say 95% because i used to think it was always guranteed but I have had the odd ocassion that it stumped me