The Model assisted estimators are approximately design unbiased, consistent, provides robustness and reduce design variance if underlying model reasonably defines the regression relationship. If the model is mis specified, then model assisted estimators might result in an increase of the design variance but remain approximately design unbiased and show robustness against model-misspecification. The well-known model assisted estimators, generalized regression estimators are members of a larger class of calibration estimators. Calibration method generates calibration weights that meet the calibration constraints and have minimum distance from the sampling design weights. By using different distance measures, classical calibration approach generates different calibration estimators but with asymptotically identical properties. Later, the constraint of distance minimization was reduced for studying the properties of calibration estimators by proposing a simple functional form approach. This approach generates calibration weights that prove helpful to control the changes in calibration weights by using different functions of auxiliary variable’s values. This paper is an extended work on model assisted approach by using functional form calibration weights. Some new model assisted estimators are considered to get efficient and stabilized regression weights by introducing a control matrix. The asymptotic un-biasedness of the proposed estimators is verified and the expressions for MSE are derived in three different cases. A simulation study is done to compare and evaluate the efficiency of the proposed estimators with some existing estimators of population total.