'Dim' = dimension = define variable and type (see online Help)

'Option Explicit' = Require all variables to be explicitly Dim-ed (see online Help)

I think your original code 

sq = sp
made sq a variant with an array in it (not sure)

Use the [Go Advanced] and the paperclip icon to attach a file to your post, not Dropbox or some other file storage site

but That is Not what I want
What do you want?


I didn't try to run anything


 Option Explicit     '   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Private Sub ComboBox1_Change()
    Dim j As Long   '   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    If ComboBox1.ListIndex = -1 Or ComboBox2.ListIndex = -1 Then Exit Sub


   For j = 1 To 3
      Me("TextBox" & j) = ComboBox2.Column(j + 3 * ComboBox1.ListIndex)
   Next
End Sub


Private Sub ComboBox2_Change()
    M_calc
End Sub


Private Sub TextBox1_Change()
    M_Box 1
End Sub


Private Sub TextBox2_Change()
    M_Box 2
End Sub


Private Sub TextBox3_Change()
    M_Box 3
End Sub


Sub M_Box(Y)
    ComboBox2.Column(Y + 3 * ComboBox1.ListIndex) = Me("TextBox" & Y)
    M_calc
End Sub


Sub M_calc()
    Dim sp(0 To 6) As Double    '   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    Dim sq(0 To 6) As Double    '   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
'    ReDim sp(6)                '   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
'    sq = sp                    '   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    
    With ComboBox2
       For j = 1 To 19 Step 3
           c00 = c00 + Val(.Column(j + 0))
           sp(j \ 3) = Val(.Column(j + 1))
           sq(j \ 3) = Val(.Column(j + 2))
       Next
       .Column(22) = c00
       .Column(23) = Application.Max(sp)
       .Column(24) = Application.Min(sq)
       Frame1.Caption = Space(2) & .Column(22) & Space(14) & .Column(23) & Space(10) & .Column(24)
    End With
End Sub




Private Sub UserForm_QueryClose(Cancel As Integer, CloseMode As Integer)
   Ark1.Cells(1).CurrentRegion.Offset(2).Value = ComboBox2.List
End Sub