Printing a named area - why won't it work as expected

The macro below works but … Excel does not seem to respect the print area and I find it necessary to specify From 8 to 8 in the printout statement. This is regardless of whether I use a scope of ‘Output’ or ’Workbook’

Defined names follow :-

Name Value Refers To Scope
Print_Area =Output$!$K$1:$T$40 Output
Single_Invoice =Output$!$K$1:$T$40 Workbook

If I use From 1 to 1, it prints 1st page of 1st sheet only, rather than the named area on the sheet ‘Output’

Any ideas would be most appreciated.

Sub PDF_Prt()
'Print a single Invoice to PDF
Worksheets("Output").PageSetup.PrintArea = "Single_Invoice"
Worksheets.PrintOut _
From:=8, _
To:=8, _
Copies:=1, _
Preview:=False, _
ActivePrinter:="CutePDF Writer", _
PrintToFile:=False, _
Collate:=True, _
PrToFileName:="", _
IgnorePrintAreas:=False

End Sub

Thank you Trevor for trying ...but alas same unfortunate result.

TMS - thx - I have attached a de-natured version of the ssheet.
The operative sheet is 'Selection', and clicking on the pdf icon fires off the macro PDF_Prt. Whilst the macro is set to print from page 8 to 8 .. it sort of works ...but if I change anything on (say) the 1st sheet, that causes the output to add an extra page, the macro won't give the desired result.
Of course if Excel would 'respect' my named range to 'Output!:$K$1:$T$40 ... it should work regardless of contents of earlier sheets and all would be sweet.

Brilliant Trevor !!! It worked wonderfully

Now two LAST Questions
1) Why did it work and why did my macro NOT work ? (I don't expect you to write a 5 day macro course into 1 paragraph)

2) Can you recommend any good text books on VBA ? - I looked at 'VBA for Dummies' and it didn't answer any of my questions ...maybe I am too dumb :=) !

Finally THANK YOU for your efforts and generosity