Not necessarily. The commas are probably being used to indicate pauses, not as 'parenthesis' around a clause.That may be one way but then neither comma is required. If the comma before 'except' is used then it implies their would be more after the clause.
For what it's worth, I think that the commas are desirable, even if perhaps not grammatical essential, in the version I suggested. Try removing the commas and then reading it out loud. I would think that it will either sound odd (and be quite difficult to say) without any pauses where those commas are - or else you will automatically/subconsciously insert those pauses (pauses which. in the written form, would/could be represented by commas).
Whatever, I think we are agreed that the material in question could/should have been written more clearly.
Kind Regards, John[/QUOTE]