FFS leave GST alone Chippy

[king1]

all other things being equal, most definitely YES - but as you mention earlier, other factors like supply issues and natural disasters affect market prices, all the time to be honest, so expecting the price for some items to be the same week on week is illogical...  The reality is a kilo of Kumera on that day in your scenario would have been 6.30 ish if it was not for the GST free. 

You cannot assert that the GST free but doesn't work and use unrelated market movements due to other factors as the the reason...

Which means over time there will be no way to show if GST has just been absorbed into the price - which just exactly what experts, including the Minister of Finance, have been saying.  The very reason Grant Robertson poured cold water on the idea in May.

Just because you can't show something isn't happening doesn't mean it will,  sellers cannot simply increase there prices at will with no impunity, supply and demand dictates the price, nothing else.  But yes there is bound to be some greedy bastard who thinks they can get away with a price rise at the same time...