We usually calculate TO performance using provisional load sheet data plus a 1000kg additive.
When we receive the final load sheet as long as the TO Weight is less than or equal to the weight we used for calculations we don’t redo the performance figures.
Landing calculations usually done prior to ToD using estimated landing weight. No further calculations required unless the conditions change for the worse. Usually not a problem as we aren’t usually landing distance limited at the airports we operate to.