While showing the plot, Developer showed the wrong spot bymistake

Last week I was shown a plot at an "open view spot" in a project by a developer in his 500 acre project near pune. I was told that name and area of that "open view plot" are A7 and 13000 square feet respectively. Last week I registered A7 plot at registrar office. When I revisited the site, sales office person told me that "open view spot", which was earlier shown to me, is actually B1 and has 15000 square feet area. One, which I have actually registered (A7: 13000 Sq ft ) is adjacent to B1. Now I want the spot which was originally shown to me (technically B1) as it has much better "open vie". sequence of plot is......B2 | B1 | A7 | A6..... 1. Developer is accepting his fault and ready to help me by making a deed on 100 Rs stamp paper. They are yet to tell me the exact procedure. They are saying that I just need to pay for extra 2000 square feet. 2. I don't have problem in paying the difference amount because of the extra area of B1, but in registration deed they have clearly mentioned that plot A7 has B1 in its West and A6 in its East. Now if they change the plot name, it might contradict with this info. 3. If I re-register the new plot (B1), and sell the previous one(A7) back to developer, will there be any extra liability of stamp duty etc? 4. Can the developer change the numbering of the plots which are adjacent to each other and not sold yet. What's the best way to sort I out? Developer is ready to help and he is accepting his mistake and luckily B1 has not been sold yet. Thanx in advance