I noticed LibreOffice Basic evaluates the with expression every time the object is used within the block. This prevents optimizing some code where the object can be evaluated outside of a for/to loop, and then re-used for each iteration.

Workaround is to evaluate the expression to an object and then use that object in the with expression.
For example instead of:
With getsheet
Use:
oSheet = getsheet
With oSheet

This is different behavior compared to Excel VBA, where the object expression is only evaluated at the start of the block. Verified in Excel 2010, almost certain 2007 was the same, but not sure about earlier versions.

Example in LibreOffice Basic:-
Sub Main
	Dim i As Integer
	With getsheet
		For i = 0 To 9
			msgbox (.getCellByPosition(0, i).Value)
		Next i
	End With
End Sub
Function getsheet As Object
	msgbox "getsheet was called"
	getsheet = thisComponent.Sheets(0)
End Function

Similar example in Excel VBA:-
Sub Main()
    Dim i As Integer
    With getsheet
        For i = 1 To 10
            MsgBox (.Cells(i, 1).Value)
        Next i
    End With
End Sub
Function getsheet() As Worksheet
    MsgBox "getsheet was called"
    Set getsheet = ThisWorkbook.Sheets(1)
End Function