Question Re: using "Rewards" at DUCA to increase GIC rates | DUCA Credit Union | Discussion forum

I logged into my DUCA account and noticed that I have earned Flex Rewards. It says that I can apply Rewards to get a better rate on GIC's or Mortgages.
I have read that it can be as much as a 10% difference in rates. (I cannot find where I saw that tidbit of info yesterday when I was exploring how to use my rewards on the DUCA site).
I think that they are talking about 10 % of the rate i.e. there posted 5 year rate today is 4.5% and it appears to me that if I have enough rewards, I could increase that rate by 10% to 4.95%.
I have not talked to a CSR and I know that I have not earned many rewards yet. I have less than 25 "Flex Rewards" and apparently you can earn as many as 1,000 per year.
My question is: Has anyone done this and how many rewards does it take to increase a GIC rate.