I love it when I meet an Italian word that resembles others from different Romance languages. This one, piuttosto, looks like and means the same as bientôt in French and més tost in Catalan: more + soon, i.e. sooner, which is one of the meanings of rather, and metaphorically transforms into the others.
And that is correct. Most DL languages are more sensitive for the linguistic nuissances and fine differences in meaning and moods than the English. Including the Italian. Unfortunately this seems to be the most effective way to teach this. Oscar Wilde said afaik that "French are so strange, they have separate words for everything". I try to help on the Hungarian for English speakers course as a native Hungarian and I see it almost in daily frequency that our vocabulary causes many troubles for English speakers for the same reason. Italian is almost the same.