eldpa, page-17

I think it is simpler than you suggest:

You look at the yield of a hybrid and, say it is 10% or 11% or whatever, a lot better than money in the bank. There is an exit in a year or so, perhaps you have to take a haircut of 5% on the way out if they convert to equity...then you do you NPV calculations based on yield and capital gain to give total p.a. yield that is equiavelent to say a 90 day bill with interest paid quarterly.

The only call you have to make on the equity is that the company survives......so once ELD restructured and TPI restuctured and Brookfield flexed its muscles, then the hybrids or notes became "safe and attractive"