Chopper didn't say he has exactly 10minutes of the 30 left. He said he has
less than 10 minutes left which could range anywhere between 1 and 9 minutes left.
Why should we prioritize one information over the other when both could be correct anyway?
Chapter 1012 says that a few dozen of minutes went by
A few dozens minutes starts at 24 minutes+
In the new Chopper information, as stated, this is what it says
> Transformation limit extended to 30minutes
> Chopper having
less than 10 minutes left
This means that since Chopper first transformed in MP, it lasted anywhere between 21 and 29minutes
So as mentioned both informations can be correct, with the most accurate timeframe looking more in the 24minutes+ range
As for this part
What you forget is that one piece characters move at superhuman speed. All of this could have happened in less than 1 minute.
Hell Kid even said Zoro's hakai feat only lasted a second