It is strange to me that the LB designation would get him more than the Edge designation since the highest paid LB in the league is making $20 million per year. 12 Edge/DE players are making more than that already. And when it was announced the Cowboys picked up Parsons' 5th year didn't the tweet say it would cost Dallas $2.1 million more than the LB designation? The facts seem hard to come by.
In any case, I thought the designation was based on some CBA rules based on the number of snaps at each position.
In the end, it is not going to matter because in all likelihood Dallas is going to give Micah an extension next year and none of this will matter.