The information pre-filled on my BAS return when I am lodging online is different from the information pre-filled on my BAS return if I were to lodge manually. For example in my March BAS GST on sales 1A was $8307 on the manual form and $4803 on the online form, and the GST on purchases 1B was $2156 on the manual form and $1724 on the online form. How can I find the cause of this discrepancy?