Greetings. I submitted a POI a few days ago, for Zek, and found out last night that it's wrong, as are more than a few others. This is fact so please keep an open mind, as i'm certainly not flaming. Peeps need to know this and these POIs need to be deleted.
All gravestones, be they Sullon, Tallon, or Vallon are not static. They pop according to who goes by or whatever. I haven't found a single gravestone of any of those three mentioned in the locs of the relevant POIs. I have however found quite a few of the gravestones, in completely different areas of Zek.
The Darkened Den, a POI i submitted I found to have popped a long way from where i first saw it. The next day, it had popped against the wall about halfway up Titans Tower!
The Sullon Mines I found in no less than three different and widely spaced locations. If there are other mines than they likely pop in several locs also.
I hope this helps. Anything else i see i'll be sure to post. Take care all