I suspect there is no simple way to address this during the merge, however should be simple enough to produce a macro to ensure there were the appropriate number of empty paragraphs in each cell to produce the required spacing after the merge.
The following macro assumes that there are twelve empty paragraphs and four populated paragraphs at the top of each cell (including 1 value below the coloured line). Merge to a new document and then run the macro.
Code:
Sub Macro1()
'Graham Mayor - https://www.gmayor.com - Last updated - 19 Sep 2021
Dim oTable As Table
Dim oCell As Cell
Dim oRng As Range, oLast As Range
Dim i As Long, j As Long, k As Long, m As Long
For Each oTable In ActiveDocument.Tables
For Each oCell In oTable.Range.Cells
Set oRng = oCell.Range
j = 0: m = 0
For i = 1 To oRng.Paragraphs.Count
If Len(oRng.Paragraphs(i).Range) > 2 Then
j = j + 1
Else
m = m + 1
End If
Next i
Debug.Print j & vbTab & m
If j > 4 And m = 12 Then
For k = 5 To j
Set oLast = oRng.Paragraphs(oRng.Paragraphs.Count - 1).Range
oLast.Delete
Next k
End If
Next oCell
Next oTable
lbl_Exit:
Set oTable = nothinh
Set oCell = Nothing
Set oRng = Nothing
Set oLast = Nothing
Exit Sub
End Sub