Interesting SOP...
Reference Airbus 15th Performance and Operations Conference in Puerto Vallarta, 23-27 APR 2007:
"Operation in Icing Conditions in Flight...Ice Crystals: An Environmental Threat" by Helene Rebel
Specifically, this discussion was centered on the GE CF6-80E1 and the RR T500. But, the impression I got when reading this is that the principles can apply to all airframes and engine manufacturers/models.
There is a reason why the Airbus and Boeing SOP is what it is.....
The Airbus FCTM is another good reference with regard to this topic.
PantLoad