The switch decides whether the upload only sets the dated menu quantity or also changes on-hand stock:

• Off (Menu only) - each row writes the Quantity Needed for that meal/portion on that location's menu for the date. On-hand stock is untouched and no stock movements are created.
• On (Sold) - each row additionally writes a stock movement of -qty with the reason Sold, lowering the location's on-hand stock, and the review shows On-Hand Stock old -> new for every line.

The switch's starting position comes from Client Config > Retail > Retail Menu Upload Stock Adjustment Default (deduct uploaded quantities as "Sold"); whoever runs the upload can still flip it for that run, including on the review screen. When deducting, several rows for different dates that hit the same meal/portion/location are accumulated so the projected stock is correct.