The discount rate is supposed to reflect the risk free rate of...

The discount rate is supposed to reflect the risk free rate of return (i.e. what could you get as a return 'risk free' as an alternative). US Treasuries are often used or a companies WACC. And whilst many pundits increase the discount rate to reflect any increased risk (say looking at a small cap volatile cashflows vs a large cap or a large cap miner with mines in Africa vs mines in Australia, or looking at a clinical stage biotech vs a BP) KJT already provided for this risk by discounting the value (chance) of each cashflow separately rather than putting it in the discount rate.

So while he may have used a 8-12% as the 'discount rate' some of those cashflows were only given a % chance of occurring based on average approvals which effectively increases the discount rate (a 50% chance of getting approval applied equates to a doubling of the discount rate used, a 33% chance triples the discount rate applied, etc)

Not sure what discount rate was used by @Kjt1969 though?