Did a little workaround, but not sure if this is the best practice... anyway.. :) hopefully somebody will make good use of this in the future. :)
var metrics = from m in data where m.CreatedDate > lastUpdate orderby m.CreatedDate ascending select new { m.LogType, m.Category, m.Item, m.UDC, m.CreatedBy.LookupValue, m.CreatedDate, m.VisitingUrl.Url, region = m.CreatedBy.LookupValue.Substring(0, m.CreatedBy.LookupValue.IndexOf("\\")) };
var nextRow = worktable.RowCount() + 1;
Console.WriteLine("Number of items to be added: " + metrics.Count());
if (metrics.Count() != 0)
{
worktable.InsertRowsBelow(metrics.Count(), true);
var tableWithData = worktable.Cell(nextRow, 1).InsertData(metrics.AsEnumerable());
workbook.SaveAs(localPath);
}