Regarding buyback of PXUPA.It can probably be done.Have a look...

Regarding buyback of PXUPA.
It can probably be done.

Have a look at AGI - they have 8% convertable notes with a face value of $1.30.
AGI declared a buyback when they were trading around 80c,
This buyback slowly increased in price to face value.
I expect it was profitable for them because the bulk would have been bought back under face value.

Unfortunately for me I was not patient enough and sold (still at a small profit) before the buyback.

Its hard to be patient but it can bring big rewards.