BSOP for company valuation

doubt i)
Sir this is a line written on finding the ‘Pe’ when using BSOP for company valuation:

“For the exercise price, the debt of the company is taken. In its simplest form, the assumption is that the borrowing is in the form of zero coupon debt, i.e., a discount bond. In practice such debt is not used as a primary source of company finance and so we calculate the value of an equivalent bond with the same yield and term to maturity as the company’s existing debt. The exercise price in valuing the business as a call option is the value of the outstanding debt calculated as the present value of a zero coupon bond offering the same yield as the current debt.”

the last line in this paragraph seems slightly amiss to me. For Pe we always use the future value of investment/cash flow, without discounting, right? So why does this last line state that it is the “PV of ZCC”? And i know from the calculation that after finding the PV of our redeemable debt(its MV), we compound it for the same time as and yield as our bond to arrive at the expected future value of ZCC, which also happens to be our Pe.

Would you mind making things little clearer, sir?

doubt ii)

Sir as far as “Pa” is concerned in BSOP model for company valuation how is it found out? Total assets less current liabilities? Or net assets?