Amount shown in GST03 Return not tally with GST Details for total input (6b) and output tax (5b)
When you save as draft, the system will save all the figures and system still allows u to enter other transactions in this taxable periods.
Thus, your draft GST Tax return may have different figures compare to your actual source transactions.
Anyway, if you go back to the Draft Tax Return and click a button "Re-Generate Draft Data" then you should be able to see the figures are now refresh and tally with the source data.
After you click the button "Submit Tax Return" and submit successfully, the status of the tax return will become "Submitted" and now you cannot modify or input any transactions within this taxable periods.