When creating a quality control point (which will later creates the quality checks), make sure to select "Quantity" when setting a value for the field, "Control per".

Once you receive the item and separate the quantities into their respective lots, Odoo creates multiple quality checks. Let's assume you received 100 units and these are divided in three lots:

• Lot A = 30 units
• Lot B = 50 units
• Lot C = 20 units

When you first validate the purchase order and the receipt is created, there is only one quality check:

After you create the lots and set the quantities, Odoo splits the check.