If you are using I&WS and you are using more than one layer of underlayment (felt or I&WS), then it makes sense to sandwich the flange. However, if you are only using felt, the felt needs to go over the flange of drip edge at eaves.
How do I do it? Well, lets say you have a 5-inch deep gutter. On those occasions when I actually do some roofing instead of directing others, I use a full-width of I&WS along the eave and extend it down the fascia board about 4-inches (so gutter still covers it). I install the drip edge, then install 30# felt starting at the eave and covering the drip edge flange, and work my way up slope in a shingle fashion. I will also use I&WS as extra protection around roof penetrations and in valleys. My thoughts about the gutter detail is this: With the I&WS extended from the roof deck down over fascia board there will be no chance for water or ice-damming to rot out the fascia board if it gets behind the gutter. In addition, ice and water can not back up far enough to enter residence from the roof because of the I&WS on the deck along perimeter. If the shingles leak and water travels down the roof on the 30# felt underlayment (and beneath the shingles), it will be directed over the drip edge and into the gutter. I've done it this way for years and have never had a problem, because the entire edge is sealed watertight.
However, if you are ONLY using one layer of felt underlayment, the felt should be placed on top of drip edge at eaves, and beneath along the rakes in accordance with the manufacturer's and NRCA's recommendations/requirements.