int RowOffset;
int StartBundleRow = 11;
for (RowOffset = StartBundleRow; RowOffset < bundleRows + StartBundleRow ; RowOffset++)
{
worksheet.Rows[RowOffset].Insert();
worksheet.Cells[RowOffset, "D"].value = srcBundlePanel.Controls["txtQtyBundle" + RowOffSet].Text;
}
RowOffset += 6;
Using a counter variable declared outside the 'for loop, then you can use that when the 'for loop exits.