The value of the Lovenox royalty stream to another company that pays taxes must be computed on an after-tax basis; hence, the after-tax value is what dictates how much MNTA could expect to obtain by monetizing this asset.
That makes sense IF you will sell the royalty stream.
But when it is worth 100% to MNTA but only 70% (1-tax discount) to the buyer, then - no sale is rational and I would value at 100%.