User blog comment:Hayashi H/Winter 2016 Guide/@comment-26154973-20160217085122/@comment-26486243-20160219090205

According to the sources Qunow's been mentioning, the Submarine Princess in E1 might have received a ~22 armor nerf a few days after the event started (ergo, it's applied now), which would significantly reduce the difficulty of clearing it. I haven't had time to verify it though.

Should his numbers be right, Saiun becomes important since 71 armor is well within the range where the Princess in sinkable in head-on.