Carpet Area and penalty for delay in construction

I had entered into sale and conston agreement during the month of Apr'14. After that, I applied for a home loan at LIC HFL. First disbment was made on 30th May'14 ,12.3 lakhs. I called up the builder and told him that I want to complete the registration by July. Builder had agreed and he told that the guide line value has been increased from Rs.1300 per sq.ft to 1450 per sq.ft so he wants to make changes in the Sale deed for which I agreed. He then forwarded the draft of registration document to me. In that draft, I found that the Vendor name has been changed and it is nothing but one of the employee of Builder. When I enquired, the builder told that they have transferred the signing authority to this person after board meeting which was held on 16th June. Hence, this person will be signing in registration documents on behalf of the builder. Is this OK. General power of attorney exists between owner and the builder which was executed in the month of May'14.