The author is factoring in about 30c p/t from the cash component and about $3 p/t from future royalties (2% of $150 p/t for DSO) arriving at $3.32 p/t.
Yes it's a flawed way to value the deal, the royalty may never come and to use $150 p/t as the sale price for any future royalty is clearly a stab in the dark.
