This morning I found a number of the mesh creators posting about Collada upload problems. Check this thread: Can’t upload in the new viewer.
Since some experienced mesh creators are having problems and it is more than one, it seems to be a viewer problem.
It seems once a problem LoD version of the model is included, the uploader goes nuts and cannot recover. The grayed out upload and calc buttons never recover. A viewer restart clears the buttons but not the particular LoD version problem.
Charlar Linden has seen the thread and is watching for their JIRA.
This version is the one that changes labeling from Prim Equivalence to Land Impact. It has been so long since I’ve used the main viewer I forget people have been dealing with PE all this time. Hopefully the change to Land Impact and the new Linden post on how it works will help people better understand Collada Model costs.