We present a sufficient condition for a Banach space to have the approximate hyperplane series property (AHSP) which actually covers all known examples. We use this property to get a stability result to vector-valued spaces of integrable functions. On the other hand, the study of a possible Bishop-Phelps-Bollobas version of a classical result of V. Zizler leads to a new characterization of the AHSP for dual spaces in terms of w*-continuous operators and other related results.