In Dragonball Z Kai there are two different English dubs: the TV version and the DVD version. They handle the famous "what is his power level" scene differently.
Nappa: Vegeta. Vegeta! What's wrong with you?! Tell me what his power level is!
Vegeta: It's over nine thousaaand!!!
Nappa: What?!! Nine thousand?!!
Nappa: Vegeta! What does the scouter say about his power level?
Vegeta: It's over eight thousand!
Nappa: Eight thousand?!!
While I presume that Nappa's first line was just a result of a different take or a slightly different wording, I'm confused especially about how the TV version (and all previous English dubs of Dragon Ball Z, shown earlier in the video) gives Goku's power level as "over nine thousand", while the DVD release of Kai changes it to "over eight thousand".
The two numbers have the same number of syllables, so it doesn't seem like something that would have changed to accommodate lip flaps or anything. So why the numerical change from 9000 to 8000?