I don't know. It's my guess his kung fu's improved. He always used to practice harder than anyone else and he's probably added some variations.
10 seconds sound clip from the The Woman Avenger (1980) movie soundboard.
You can hear this line at 01:14:28 in the DVD version of the movie.
Quote context
[...]
- You have done well. In just a short time you've learned everything I know.
- It depends on you, you're going to have to be strong.
- Sister, do you think my kung fu is enough to defeat Quang Fu Chi?
- Also, I had heard he had learned a new secret technique.
- A new technique? What is that?
- That's it, I don't know. I have never been able to get close enough, but I know that he has one.
- Don't worry. Well sister, I believe that I will beat him.
- Buddha will see that we win in the end. A dupper like that can't win.
- I've thought about this for a long time, but I think it's right you know.
- It's the secret Twin style of boxing. I was sworn to secrecy about it.
[...]