fpa-au-gst-baslisted

# Australian GST and BAS cash timing Use when forecasting cash for a GST-registered Australian entity. GST collections and BAS settlements create material cash swings that a naive P&L-to-cash bridge misses entirely. ## Workflow 1. Establish facts (intake): BAS cycle (quarterly default; monthly mandatory at $20m+ GST turnover), share of GST-free or input-taxed revenue, share of purchases without input tax credits, whether a tax/BAS agent lodges (extensions). 2. Compute the monthly net GST position from GST-EXCLUSIVE series: ```python from pyfpa.au import BasCycle, GstAssumptions, bas_schedule, monthly_gst gst = monthly_gst(revenue_ex_gst, purchases_ex_gst, GstAssumptions(bas_cycle=BasCycle.QUARTERLY)) schedule = bas_schedule(gst["net_gst"]) ``` 3. Feed the 13-week model: ```python from pyfpa.au import gst_weekly_flows receipts, disbursements = gst_weekly_flows(schedule, window_start="2026-10-01") config.receipts.extend(receipts) config.disbursements.extend(disbursements) ``` 4. Reconcile: management P&L (GST-exclusive) versus bank cash (GST-inclusive). Receipts in the cash model should run ~1.1x taxable revenue; the difference accumulates as a GST liability until BAS settlement. ## Due dates Original due dates only (28 Oct / 28 Feb / 28 Apr / 28 Jul quarterly; 21st following month for monthly). Agent lodgment program extensions are NOT modelled; forecasting on original dates is conservative for pay