Hmmm. Going with your suggestion of using autotext, save your document as a macro enabled template, then select the bottom two rows of your second table, press ALT+F3 and save as an autotext entry called
ItemAction in the template.
The following macro will then add the autotext entry to the bottom of the table when you tab out of the last cell (the first table should still tab normally) as should tabbing between other cells.
There is some anomaly related to bullets, when you add text to the cells just added, but the basic issue of ease of use for your users is resolved.
Code:
Option Explicit
Sub NextCell()
Dim iWidth As Long
Dim iCol As Long
Dim iRow As Long
Dim oRow As Row
Dim oRng As Range
Dim oCell As Cell
Dim oTable As Table
If Selection.InRange(ActiveDocument.Tables(2).Range) Then
Set oTable = ActiveDocument.Tables(2)
Set oRow = Selection.Rows(1)
iRow = oRow.Index
iCol = oRow.Cells.Count
Set oCell = oTable.Cell(iRow, iCol)
'If the cursor is not in the last cell of the table, move to the next cell
On Error GoTo lbl_Exit
If Not Selection.InRange(oCell.Range) Or _
Not Selection.InRange(oTable.Rows.Last.Range) Then
Selection.Cells(1).Next.Select
Selection.Collapse 1
GoTo lbl_Exit
End If
Set oRng = oTable.Range
oRng.Collapse 0
Application.Templates(ThisDocument.FullName). _
BuildingBlockEntries("ItemAction").Insert _
Where:=oRng, _
RichText:=True
Set oRow = oTable.Rows.Last.Previous
oRow.Cells(2).Range.ListFormat.RemoveNumbers NumberType:=wdNumberParagraph
oRow.Cells(3).Range.ListFormat.RemoveNumbers NumberType:=wdNumberParagraph
'select the first cell of the new row
oRow.Cells(1).Select
'move the selection to the start of the cell
Selection.Collapse 1
Set oRow = oTable.Rows.Last
oRow.Cells(1).Range.Paragraphs(1).Range.ListFormat.RemoveNumbers NumberType:=wdNumberParagraph
oRow.Cells(2).Range.ListFormat.RemoveNumbers NumberType:=wdNumberParagraph
oRow.Cells(3).Range.ListFormat.RemoveNumbers NumberType:=wdNumberParagraph
Else
Set oRow = Selection.Rows(1)
iRow = oRow.Index
iCol = oRow.Cells.Count
Set oCell = Selection.Tables(1).Cell(iRow, iCol)
If Not Selection.InRange(oCell.Range) Or _
Not Selection.InRange(Selection.Tables(1).Rows.Last.Range) Then
Selection.Cells(1).Next.Select
Selection.Collapse 1
GoTo lbl_Exit
Else
Set oRow = Selection.Tables(1).Rows.Add
'select the first cell of the new row
oRow.Cells(1).Select
'move the selection to the start of the cell
Selection.Collapse 1
End If
End If
lbl_Exit:
Set oTable = Nothing
Set oRow = Nothing
Set oCell = Nothing
Set oRng = Nothing
Exit Sub
End Sub