Thanks. I was getting an unrelated error that led me to believe I needed to pass data to the grid on instantiation. I resolved that bug and add/remove rows is working fine. 

i do it this way:

jQuery("#tDatos").addRowData(0,{dato:"Cantidad de prendas",pesos:" <?echo $cantidadPrendas?> "});
jQuery("#tDatos").addRowData(1,{dato:"Costo de prendas",pesos:" $<?echo $totalCostoFabrica?> "});
jQuery("#tDatos").addRowData(2,{dato:"Precio de venta",pesos:" $<?echo $totalPrecioVenta?> "});
jQuery("#tDatos").addRowData(3,{dato:"Diferencia",pesos:" $<?echo $totalPrecioVenta - $totalCostoFabrica?> "});

tDatos is the table, dato and pesos a are columns and the first number is the row position