Afaik they were only to the left of the registered route by say a mile. They'd failed to go through the DP pass the previous day (probably due to lack of crampons, ice axes ropes etc) and had lightened their loads (labaz) before going to the left of the DP on the last day. It makes sense that they camped up there to recover time by bypassing the forest. Or maybe Semyon wanted to photograph something up there....