If I am reading this right, if the 5 blade option is too expensive / complex and little to be gained, could this be why ECD have gone for a "CAT A" switch on the EC135T2? Increase the RRPM by 3% for class 1 take off / landings and get the benefit of increased lift with a greatly reduced cost implication.
Now the EC145 comes with an automatic increase if RRPM at low speed (below 55Kts I believe), so why keep going down the extra blades route?