What happens if tds deducted is much more than tax liability

For salaried people generally TDS is deducted from salary of each month based on estimated probable tax liability for the FY (calculated at the beginning of FY). Suppose this uniform deduction is made April to November and after that employee is asked to submit details of tax liability (including income from all sources and all possible deductions under 80C,D etc along with supporting documents) and if net tax liability is found to be greater than previous estimate, then TDS is increased accordingly to cover remaining income tax over the remaining months of the FY. (This may happen due to maturity of fixed deposits etc which were not considered earlier by the office) My question is suppose, to be on the safe side I give an estimate of income tax liability neglecting large deductions which is likely to take place later in the FY but I am not sure at the moment. So TDS deducted is excess of actual and is reflected in form no 16. At the time filing return I can claim the excess tax paid. But will there be any problem if the refund amount is huge? In extreme case, if refund amount is larger than total tax paid (TDS), then what will happen? Will the assessee get back all the TDS paid?