The NTSB report is available online.

The airplane performance study and simulations showed that the airplane experienced minimal performance degradation because of ice accretion.184 Specifically, the AOA at the time of the wing stall was about 1° above the expected AOA for a clean wing (no ice accretion) stall warning. Thus, the airplane could have been operated in normal flight, at the non-icing Vref, and with a substantial margin remaining above the actual point of stall. As a result, the NTSB concludes that the minimal aircraft performance degradation resulting from ice accumulation did not affect the flight crew’s ability to fly and control the airplane. The flight crew’s actions during the accident sequence are further discussed in sections 2.2.2 through 2.2.4.

I amended this to the other post. The crew configured the aircraft outside the marker and pulled the power to idle, they left the power at idle until the aircraft stalled. The stall was right on the calculated AS for a wing with no ice or other contamination.