they are trying to "retire" as many shares as possible.....
so they don't have to buy them from future market activity when a merger or takeover is announced and the stock gets more expensive.
25MM and 40MM days seem to denote a future owner is trying to garner majority ownership or voting right shares for an eventual owner change.
Once a plausible rumor starts circulating that a viable operation is interested in the "shell" of PWTC as a presently trading company, the buying will begin again and acquiring additional shares to attain "majority ownership" in the open market will cost much more than sneaking in on these quiet days to slurp up a few million at a time.
We may still have Billions in issued and outstanding shares...... so there is a lot of buying to be done before "the float" gets reasonble and upward responsive to buying pressure.