A little reading last night showed that the guys down under were on crack way back when too. See RDH4, chapter 13, section 5, pages 571 and 572. In particular is the passage...I'll paraphrase...If you remove one valve the effective load resistance on the remaining valve becomes 1/4 a-a which is what it would be in class AB when one of the valves reaches cut-off.

I'll neither confirm nor deny this post if a certain transformer winder should happen to read it:)

Later gators!