What is SANS stamp worth?

I installed a readyboard and discovered on site that the 20A plug circuit was in fact a 1.5mm circuit.
After going back to Voltex I gave them an earful. I had to leave site, drive across town in bad traffic and waste an hour at the counter, then buy a lower rated CB because they are selling DBs which do not meet the standards.
They still sell them.
Now I must just explain to the homeowner why I am charging him for my time to rewire a prewired DB which has the SANS stamp on it.
Why bother with the stamp if we must check the internal wiring in any case?