I presoak in trays for two reasons, even development, and, I find when adding several sheets of film to a tray, it takes many seconds to place them all in,
especially if the film is sticking together a bit (not from liquid, but from the propensity of film to stick to another film).
If I'm putting film in developer directly, this process could take from 30 seconds to a minute. With a presoak, I take the entire stack of film, maybe 6-8 sheets, and move them all into the developer at once. That way they all get the same time in the developer.