When researching on how to say dates, I came across two different instructions on the same issue: how to say years **before and after the year 2000.** (Actually I wouldn't expect to hear the rules would be different before and after 2000.)

And I tried to verify the difference and listened some native speakers. Then I saw Cambridge Dictionary and native speakers say different things when it comes to **how say the years from 2001, 2002, 2002, ..... until 2010.**

Cambridge says:
2003: **two thousand-and-three or twenty-oh-three** (source: <https://dictionary.cambridge.org/grammar/british-grammar/dates>)

A native speaker on oxford online tells to use **"full numbers after the year 2000 until 2010.**, which is exactly the opposite of Cambridge says. (See on youtube, watch between (2:40-3:00) of the video at <https://www.youtube.com/watch?v=Vw54Nu1SXcE>

why do you think there is such a difference?