I'm currently building and just got my internal lining progress payment invoice. std HIA South Australia builders contract it also has an attached variance for some downlights and switches. yet only the wiring has been run. no lights or switches etc have been installed. am I required to pay this now or are they just trying to get me to pay extra now. what's meant to be completed for the internal linings? or where do I find out? also with regards to downpipes and tanks would that be in the bricks and roof payment?