Well to answer OPs question, i can see why they didnt upgrade the turn 5 gear's ilvl to 90 because different piece are from different turns. Lets say for instance 1 job's body piece drops in turn 1 and that job's head piece drops in turn 5... they would get a bit of a stat boost with the head upgrading to 95. Now take another job that is reversed (head in turn 1, body in 5), it would be unfair because they would get way more of an increase than the first job.