a quick fix for the count problem was adding the function inside a settimeout.
I still get the same error with the $("#grid_1e0fde94_6b04_413c_9ef3_9e51776134f3").jqxGrid('setcellvalue', index, 11, sumatoria);
$("#grid_1e0fde94_6b04_413c_9ef3_9e51776134f3").jqxGrid('setcellvalue', index, 11, sumatoria);