Well, everything inbetween vertical bars | is an OR condition.
So it is \d{1,2}/ OR \$ OR etc.
Unsurprisingly, the most complex of them, (?<=/|\$|\d{3,})\d{2}$(?=$) is the one that fails.
It appears that the problem is the first part of it, the zero-width lookbehind assertion.
So you could get something that sort-of works by omitting that condition and just using \d{1,2}/|/|\$|\¢
That doesn't get you the more complicated expression, which basically was:
"If you have two digits at the end of a line, followed by the end of a line (yes this is redundant!), and preceded by EITHER a slash, a dollar-sign, or 3-or-more digits."
Maybe someone who uses GREP styles more knows what broke in CS6? I haven't had a chance to test your pattern in both CS6 and CS5...