As far as we've come to understand, that is it exactly. I had friends arrive from home that were from different points within our timelines, later on down from what I last remembered, but they knew of me and events I hadn't yet lived. So we are there in some way, while also managing to be here.
But yes, I agree entirely. Vallo and its magic is unique and it's been a two year struggle to try to understand it. As soon as I think we've wrapped our heads around it, something else odd happens that blows it all down. Frustrating, but not enough to warrant quitting the exploration and experimentation, by any means.