My take is this:
PP's are to raise $X amount of dollars to fund assorted activities - BFS, drilling, etc.
Regardless of the share price (and therefore how many shares Ernesto gets for any given PP tranche) as an investor it still costs him the same amount in dollar terms. Those PP dollars are actually paying for stuff like the BFS etc.... not the shares Ernesto nets in exchange.
So if he commits less PP dollars, it's because less needs to be spent on real life activity.
On a side note, if he knows to wait for the share price to sink, that would imply some understanding of the stock that we don't have - yet he's not in blackout, so that shouldn't be the case either.
I think when they need it, they raise it, and their style is to raise a few million frequently, as opposed to ten's of millions infrequently. And suddenly he didn't take the full amount, less than 4 weeks ago, and on the verge of BFS completion. It seems more probable to me that he doesn't need to spend more - such as to correct a "BFS gone wrong".
