Reviving this year-old thread, I think that makes a lot of sense, as these islands were taken to launch bombing raids against the Japanese home islands, and with basically the exact aircraft types discarded in these heaps. I think we launched the bulk of these raids from Saipan, as it's the larger of the islands, thus it makes sense we'd want to pile these "totaled" ones elsewhere. But then maybe that's a little bit of a stretch...