Dynaudio and Mac

I just recently acquired a pair of Dynaudio Contour S 3.4 loudspeakers to be paired with my Mac MC402 power. Thus far, the results have been nothing short of astonishing relative to my previous B & W CDM 9NT speakers. I should also mention that I have switched to Kimber Select KS-3033 speakers cables. I had the new cables inserted into the 9NTs for one day and was very suprised at the impact these cables had on the overall sonics of my system.
My main concern is the additional gain required on my BAT pre to achieve satisfactory SPLs. For example, I now need to turn it up to 65 to rather than 50 to get same subjective level of sound pressure. The Dyns sensistivity is listed as being BOTH 88 db/w and 86 db/w on the dynaudio website. My 9NTs were rated at 89. If the 86 is in fact correct, than I can understand why the extra gain is required but I have a feeling the sensitivity is closer to 88. I am using the 4 ohm tap as suggested. Has anyone had sucess using the 8 ohm tap with Dyns?