Filling form 26QB in case of joint buyers and property transfer case

Hi All, Me and my mother purchased a unit in an underconstruction society in Gurgaon from the previous owner (reseller case). The previous owners had paid all dues except the possession demand and submitted the applicable TDS on their payments. We have now gotten the possession demand from the builder which both my mother and me will be paying 50-50. As per latest demand from builder, here are the values. Basic Property Value: 1,07,46,492 Property Value incl. GST: 1,13,06,257 Previous owners already paid: 95,24,420 Pending (possession demand): 17,81,837 (A) TDS Calculation (1% of basic property value): 1,07,464.92 TDS already paid by previous owners: 94,216 TDS pending: 13,248.92 (B) So to close the ledger, my mother and I will be doing the following payments: Me: 884294 to the builder ((A-B)/2) and submit 6625 TDS (B/2) Mother: 884294 to the builder ((A-B)/2) and submit 6625 TDS (B/2) QUESTIONS: My questions to you fine people are - while filling the form separate form 26QB, what should we enter for the following fields: 1. Total Value of Consideration (Property Value): 1,07,46,492 or 1,13,06,257? 2. Payment type: I'm assuming "Installment - Last Installment" since it is the last payment both of us will be making? Or does it depend on who fills the form 26QB first? So in case I fill it for myself first, should I select "not the last installment" and when filling it for my mother select "last installment"? 3. Whether stamp duty value is higher than sale consideration?: Builder has only provided stamp duty to be paid by us which is is 7,85,000 at 7%, which back calculated will give a stamp duty value of 1,12,14,285. Is it the right way to calculate stamp duty value? Also, should I compare this to basic property value or value incl. GST? What would be the answer to this question? 4. Total amount paid/ credited in previous installments, if any: Which value would go here? 5. Amount paid/credited currently (B): Which value would go here? 6. Total stamp duty value of the property (C) (proportionate share): What would the proportionate share to be entered here? I know these are perhaps a lot of questions, but any help here would be greatly appreciated by me and my family. Thanks very much in advance.