hetki / hetken

[Gavril]

Hello,

I just ran across the following sentences in a set of cleaning instructions:

Levitä pesuaineliuos pestäville pinnoille, anna vaikuttaa hetki.

"Spread the detergent solution on the surfaces you are washing; leave it for a while/moment so that it can take effect."

Levitä tuote hankaussienellä tai harjalla. Anna vaikuttaa hetken.

"Spread the product [on the surfaces you are cleaning] with a scouring pad or brush. Leave it for a while/moment so that it can take effect."

1. Is there a clear reason why the writer used hetki in one instance, but hetken in the other?

2. Perhaps related to question #1:
Can we resolve whether the writer meant "moment" or "while" in these cases?
(For me, "a while" is an indefinite time length, but it's probably at least a few minutes long; a "moment" could be far shorter than that.)

Thanks for your time,
Gavril

 

[Maunulan Pappa]

For me, the two expressions are synonymous and there is no difference as to the duration of time. It could be anything from a few seconds up to maybe fifteen minutes or more.