Proportionate Area Mismatch In Sale Deed

Hi, We recently brought a 2bhk apartment and took possession of the same. In one of the project documents recently shared by builder for crosschecking carpet areas for maintainence (annexure containing all types of area details for all flats), we noticed a discrepancy with respect to the sale deed. The "proportionate common area" is 21.6 sq.m. on sale deed vs 37.6 sq.m in the annexure. This area is normally used in a formula to arrive on a Super built up. All the other important details like carpet area/Super built up/UDS area/UDS % are matching. 1) Is the above proportionate common area an issue considering its non-measurable while other measurable ones (carpet/UDS) are proper. 2) Does this need a rectification deed. If yes, what would be the charges. We could not figure out the mismatch while doing sale deed because this area was not written/promised in the agreement (while booking/down payment). This mismatch has been communicated to builder and he is yet to respond