im not understanding why some of the code below works fine and some gives an error

These work fine
.PageSetup
.Borders
.Range

These give error "Option strict on disallows late binding"
.Cells
.Rows
.Columns

what is the difference???

example...
Code:
    dim oExcel As Excel.Application
    dim oBook As Excel.Workbook
    dim oSheet As Excel.Worksheet

With oSheet

'WORKING FINE
.PageSetup.Zoom = 65

.Borders(Microsoft.Office.Interop.Excel.XlBordersIndex.xlEdgeTop).LineStyle = Microsoft.Office.Interop.Excel.XlLineStyle.xlContinuous

.Range("A27").Value = "Hello"



'GIVING ERROR
.Cells(1, 1).value = "Hello"

.Rows("60:60").Font.Bold = True

.Columns("A:Z").ColumnWidth = 8.0

End With