Experimente:
Altere o trecho da rotina conforme abaixo
'wb.SaveAs sWbkFullName, xlWorkbookDefault
Columns("A:A").Select
Selection.TextToColumns Destination:=Range("A1"), DataType:=xlDelimited, _
TextQualifier:=xlDoubleQuote, ConsecutiveDelimiter:=False, Tab:=False, _
Semicolon:=True, Comma:=False, Space:=False, Other:=False, FieldInfo _
:=Array(Array(1, 1), Array(2, 2), Array(3, 1), Array(4, 1), Array(5, 1), Array(6, 1), _
Array(7, 1), Array(8, 1), Array(9, 1), Array(10, 1), Array(11, 1), Array(12, 1), Array(13, 1 _
), Array(14, 1), Array(15, 1), Array(16, 1), Array(17, 1), Array(18, 1), Array(19, 1), Array _
(20, 1), Array(21, 1), Array(22, 1), Array(23, 1), Array(24, 1), Array(25, 1), Array(26, 1), _
Array(27, 1), Array(28, 1), Array(29, 1), Array(30, 1), Array(31, 1), Array(32, 1), Array( _
33, 1), Array(34, 1), Array(35, 1), Array(36, 1), Array(37, 1), Array(38, 1), Array(39, 1), _
Array(40, 1), Array(41, 1), Array(42, 1), Array(43, 1), Array(44, 1), Array(45, 1), Array( _
46, 1), Array(47, 1), Array(48, 1), Array(49, 1), Array(50, 1), Array(51, 1), Array(52, 1), _
Array(53, 1), Array(54, 1), Array(55, 1), Array(56, 1), Array(57, 1), Array(58, 1), Array( _
59, 1), Array(60, 1), Array(61, 1), Array(62, 1), Array(63, 1), Array(64, 1), Array(65, 1), _
Array(66, 1), Array(67, 1), Array(68, 1), Array(69, 1), Array(70, 1), Array(71, 1), Array( _
72, 1), Array(73, 1), Array(74, 1), Array(75, 1), Array(76, 1), Array(77, 1), Array(78, 1)) _
, TrailingMinusNumbers:=True
For x = 2 To (Cells(Rows.Count, 1).End(xlUp).Row)
Cells(x, 2).Value = CDate(VBA.Left(Cells(x, 2).Value, 10)) * 1 + CDate(VBA.Right(Cells(x, 2), 8)) * 1
Next
Columns("B:B").Select
Selection.NumberFormat = "dd/mm/yyyy hh:mm:ss"
Cells.Select