How to customize the quantity sent to the marketplace?
Salestio synchronizes the inventory values according to the Shopify product page and Global Profile settings. To change the settings, go to Salestio > Profiles tab > Global Profiles.
“Item QTY Mode” and “Item QTY Value” are used to set the rules for quantity synchronization. For example, you can use the “Custom” mode to set the quantity at a constant value. “Product” mode is the default, and it uses the Shopify values.
Full article: Global Profiles