Why is there no blocked seat on the E190 in Europe Business Europe while the F70/100 do have a blocked (middle) seat?

Before Europe Business Class was introduced the E190 was the aircraft with the highest satisfaction score.

With the introduction of Europe Business Class certain aircraft have the middle seat blocked. Blocking the seats on the E190 would lead to a loss of 50% of capacity while it is lower for other aircraft (F70/100: 40% loss; B737: 33% loss).
As the E190 is predominantly used for short routes, taking in to account the possible loss of capacity it was chosen not to block the seat in Europe Business Class.