code: function (cell, counter) {
        var alphaNum = instance.utils.getCellAlphaNum(cell),
            alpha = alphaNum.alpha,
            col = alpha,
            row = parseInt(alphaNum.num + counter, 10);
  
        if (row < 1) {
          row = 1;
        }
  
        return col + '' + row;
      }
docs: change row cell index A1 -> A2
  @param {String} cell
  @param {Number} counter
  @returns {String}