Winforms: Incorrect and incomplete checkbox values exported to excel

I have Form1 and Form2 and one class called Savestate. In Form1, I have datagridview1 checkbox column and a label. The label will reflect the equipment name. The checkbox is initially empty. It’s up to the user to check or uncheck the checkboxes. Each checked checkbox will return a P while the unchecked checkbox will return an O. The P and O will be saved in dgv1p_list that I initiated in Savestate when user click button1. This button1 will also save the equipment name and then go to Form2.

In Form2, there is datagridview2 which reflects the equipment name. When user click Button2, the values in the dgv1p_list will be exported to excel columns B to E while their respective equipment name will be exported to column A.

However, with my code below the values exported to excel are incorrect and incomplete. With reference to Checkbox , the first and last row is unchecked so therefore Column B and Column E should be an O. But with reference to Excel, the excel results are incorrect and cells are empty. Below is my code:

Class Savestate

public static List<string> dgv1p_list = new List<string>();

Form 1

public void Intcabin()
    {
        DataGridViewCheckBoxColumn check = new DataGridViewCheckBoxColumn();
        dataGridView1.ColumnCount = 1;
        dataGridView1.Columns[0].Width = 380;
        dataGridView1.Columns[0].Name = "Item";
        string[] row1 = new string[] { "Hello"};
        string[] row2 = new string[] { "Bye"};
        string[] row3 = new string[] { "okay" };
        string[] row4 = new string[] { "thanks" };
        object[] rows = new object[] { row1, row2, row3, row4};
        foreach (string[] rowArray in rows)
        {
            this.dataGridView1.Rows.Add(rowArray);
        }
        check.HeaderText = "Status";
        check.TrueValue = "P";
        check.FalseValue = "O";
        dataGridView1.Columns.Add(check);
    } 

    private void button1_Click(object sender, EventArgs e)
    {
        foreach (DataGridViewRow dataGridRow in dataGridView1.Rows)
        {
            DataGridViewCheckBoxCell chk = (DataGridViewCheckBoxCell)dataGridRow.Cells[1];
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                if (chk != null)
                {
                    Savestate.dgv1p_list.Add(chk.TrueValue.ToString());
                }
                else
                {
                    Savestate.dgv1p_list.Add(chk.FalseValue.ToString());
                }
            }
        }
        this.Hide();
        FormsCollection.Form2.Show();
    }

Form 2

private void button2_Click(object sender, EventArgs e)
 {
     int _lastRow1 = oSheet1.Range["C" + oSheet1.Rows.Count].End[Excel.XlDirection.xlUp].Row + 1;

        for (int i = 0; i < dataGridView2.Rows.Count; i++)
        {
            for (int j = 0; j < dataGridView2.Columns.Count; j++)
            {
                oSheet1.Cells[_lastRow1, 1] = dataGridView2.Rows[i].Cells[0].Value.ToString();
                oSheet1.Cells[_lastRow1, j+2] = Savestate.dgv1p_list[i];
            }
            _lastRow1++;
        }
 }