Add database for each 'store manager' user. Change stock xfer process to add units to store database, rather than simply delete from warehouse database (as currently the case). Add a 'stocktake' process to calculate a report, as detailed below.
+ 'opening_stock' column
+ 'closing_stock' column
+ 'xfer_price' column (unit price of stock as xferred)
+ 'selling_price' column (current unit price of stock as sold in the shop)
- 'unit_price' column
e) Total xfer price value of all stock lines sold or lost since last stocktake process (Σ(b))
f) Total selling price value of all stock lines sold or lost since last stocktake process (Σ(c))
g) Total differential for all stock lines, between xfer price & selling price (Σ(d)) *See note (1)