It's very possible it (the device) works and they are waiting to find something with it before saying it works (PR) so there will be no doubt as to it's functionality. And if that is the case that would be proof also that they are not blowing hot air just to keep the PPS up. IMO

For those who are too simple minded to understand what I just said... if they kept on releasing that it worked without proof, one could say and be possibly be correct that it's all just hot air and sunshine pumping to fool investors. If this was a scam it would be more advantageous to keep releasing information than to wait. IMO