Thanks so much, Dmytro! Looks like even BB reads the Comy interpretation as importing 'past' action, probably due to the standard interpretation of jhana having first suppressed the Hindrances. I wonder if BB consulted the Tika on this?
Personally, whether we take the contemporaneity interpretation or Gombrich's more exo:tic infinitive explanation, I think both are virtually indistinguishable in the end result, ie establishment of mindfulness results IN the Hindrances being subdued. I think this is preferable to the interpretation that mindfulness results FROM the Hindrances being suppressed. That would be somewhat inconsistent with the contemplation of Hindrances in the 4th section.
However, much as I like this interpretation, I'm still puzzled by the break from the syntactic convention. I find the same syntax only in the 3rd case of aparakaalakiriyaa given by Ven D. What do you think?