Just an idea, but I would imagine the healthy discount in the...

Just an idea, but I would imagine the healthy discount in the oppies is due to the fact that expiry is around the corner - which means all the option holders need to stump up 15c to convert to fully paids. Now if some people bought a truck load looking for a good run prior to mid June then they would be happy to sell at a discount rather than convert (especially if they don't have the necessary cash to convert).
Eg. if you bought 1,000,000 options at 3c you would need $150,000 to convert to heads - that is a significant amount of cash for some investors in speculative stocks. Thus it probably is preferable to sell some on the market even at a discount, remember converting options means having a period when you can't sell.

I am not casting a negative view on PPP, I hope it does go to 30c for all holders - but that is my view on why there is a healthy discount.

I wouldn't know the exact date by which you would need to convert, but it within the next three or four weeks to make sure that you don't miss the deadline.