There still seems to be some confusion over how the correct oil temperatue is maintained. Does the oil flow switch on & off to give the desired result? if so, this could effect ice melting, which has been said to take only a few seconds when engine power is demanded? (That was said on one report, but clearly did not happen when engine power was demanded on the incident in question)
I think there wasn't enough time for the ice to melt in this situation. They had been at low power settings for a while and it simply was too late to melt any/much before they hit the ground. I think that's why the new procedure calls for periodic power increases during letdowns.