I ran a WOL report using the trinket and went through all three wings in ToT. The proc is about 1% (in Dark Animus, 112072 absorbed, 9 procs ~ 1 noncrit PW:S)
h t t p: / / www . worldoflogs.com/reports/rt-mr9zo7ikm07y6dzh/
The proc is pretty useless since Horridon's trink gives the int and also a usefull mp5 proc.