Square root of the powers, , in the first four spherical harmonics of the shock surface, weighted by the mean shock radius, as functions of time, for s15 (left) and s27 (right). Late-time SASI activity in s15 f _heat1.00 3D is apparent, as is the early ( t _pb < 300 ms) SASI activity in both s27 f _heat1.00 3D and s27 f _heat 1.05 3D. Notably, there is not so great a difference in the P _ℓ values between 2D and 3D as reported in some previous 2D vs. 3D studies (Burrows et al. 2012; Couch 2013a).