The way you're using Variants to define fixed "multi-pack" lot sizes (e.g., 5-pack, 10-pack, etc.), the Quantity shown in the cart and during checkout would be the quantity of the selected pack size -- e.g., if the buyer orders one 5-pack, this would be shown as Qty=1 for the 5-pack Variant of that product.
When we pass an order to PayPal checkout for an item with Variants, they provide no way for us to specify the selected Variant menu value(s), so we can only identify the item by its Item Name and Item Number||SKU (e.g. 1083536||AGFSC1). That SKU comes from your product's Variants configuration; it's the first value on the line defining which Variant the buyer ordered, so you might consider making that SKU more descriptive, such as "5packAGFSC" or "5-pack AGFSC1".
As another alternative, instead of using Variants, you might consider using the Quantity menu approach explained here (note your form action= URL should use your own E-junkie Client ID 207203, rather than the 68510 given in this example):
If you also want to offer volume discounts, you could set up a series of product-specific, automatic (no-code) discounts that are triggered when the cart reaches certain Min. Item Quantity thresholds for the relevant product: