It seems that the differnce between your estimates and mine is that I assume the income distribution is not flat across all 400 companies. I look for the 80/20 rule to hold. And it seems logical that PTSC has gone after the bigger returns first - so I use the past average to estimate how much the 20% might pay. In any case the 80/20 would tell me that 80% of the potential income will come from 20% of the total list of companies. That said, 80% of the companies will only contribute 20% of the total income.  I get a SP of $3 to $6 using these (conservative ?) assumptions.

Relatively small changes to assumptions can generate substantial differences in resulting totals. I hope you're right, and you could be - I like $10 and higher.