The one time fees are appropriate for now and in the future if you consider when the patents are due to expire.
Don't you think that the negotiations with DM, Edig, and the infringer have taken into consideration, at least the best they can, the future use of the patents.
We currently have no idea what products an infringer may develop utilizing the patents and if so how long and many unit sales will happen. By the same token, an alternative system or process may be developed and obsolete the use of some or all of our patents over the remaining life span.
I think that DM and the management has considered all avenues relating to income from litigation and made the correct decision.