Understanding why more timming

hello good people

a lot of topics talking about small port vs large port.
large port can handle more flow, small port have better low rev some people said large is good only above 400hp.
a lot of people say that with large port the engine can have more timing.
timing is achieved with low cilinder temp.

someone can help me understand why large port can achive more timing?

let see if i understand

more air velocity = more dynamic compression ratio = final CR is higher
more air velocity = more air in the cilinder

is this true??