I just got an email from Hertz announcing their global sale running to the end of the year. Supposedly it was 20% off in NZ. Put in my dates and the price was exactly the same even though the 'discount' code was applied. As our rental starts just before the end of the period (28th Dec) I thought perhaps it didn't apply - even though the website will usually tell you if this is the case. Tried new dates solely in December and it was about $100 cheaper. So it's the "no discount" sale unless they've jammed their prices up before offering this discount.
https://www.hertz.com.au/rentacar/a-16386272/global-sale-2014-special-offer
Edit: just did the original dates removing their sale code and replacing it with the CEB Five Stars Rewards Member code and it was $NZ200 cheaper than their "20% discount".
Thrifty still gives a better discount for NRMA membership!
What is the CEB Five Star Rewards Code you refer to? Is it a general 5 star members code? If it is, would you mind sending me the code via PM? I didn't know there was a 5 star ode, despite being 5 star for a coupole of years!