Logic on Actual Costing-Revaluation of Consumption

Hi All,

Would like to get some clarification behind the logic of Actual costing - Revaluation of consumption step. Understood the revaluation of consumption logic is to distribute the differences proportionate to quantity, to the categories consumption and ending inventory. This one is pretty clear to me until i found the following case :

Differences          : -5445

Consumption qty  : 1 Ton

Ending Inv.Qty     : 3 Ton

i was expecting the difference will be distributed as follow :

Difference to consumption : 1/4 * -5445 = -1361

Difference to Ending Qty   : 3/4 * -5445 = -4084

but SAP calculation result was :

Difference to consumption : 1298

Difference to Ending          : -6743

Please help me to understand the logic.