SteelBrick CPQ sets quantities of one for all product quantities that get pulled into opportunity product quantity. This process covers all products involved in Block or Slab discounting, allowing those features to work with SteelBrick CPQ pricing logic. However, it has no effect on quantities of assets or subscriptions generated when contracting the Opportunity.
The quantity entered for Block pricing products is used to calculate the Quote Line price before discounts. When quote lines with Block pricing sync to opportunity products, the Quantity field on the opportunity product will be set to 1, thus becoming the Effective Quantity on the Quote Line.
An organization's Wireless Router product has Block pricing with the following Tiers:
If a user enters a quantity of 10, the price before discount will be $2,000, not $16,000 (8 * 2,000) - this is because block prices are not unit prices, so they aren't multiplied by the quantity. The effective quantity in this example is '1', and that value that will be synced to the opportunity product quantity field to ensure the pricing is correct.
The quantity entered for Slab products is used in the calculation of the discount % applied to each unit. Because the per unit discount percentage can vary across units depending on the tier, the quote line does not have a consistent per-unit price. When quote lines with Slab discount schedules sync to opportunity products, the Quantity field on the opportunity product will be set to one - again becoming the Effective Quantity on the Quote Line.
If you would like to display the quote line quantity (entered by the user) on the opportunity product, you can create a custom field on the opportunity product to pull from the quantity field instead of the effective quantity. You can then hide the standard quantity field if it doesn't need to be displayed.