Well, as said above, you are halfway across the world.
I’m genuinely curious whether/where this form is idiomatic in English speaking pockets of the world. I don’t recall that being standard usage in the major non-US varieties of English, but it’s not like I’ve ever done a formal survey, either.
If anyone said “point five liter of…” to me, I’d laugh out loud. It sounds ridiculous to me, but I’m open to the idea that other areas have different conventions. Honest question for the non-plural fans out there: What would you say if it was zero (or negative)? “I have zero liter of…”? “There was an average change of -10 pound…”? It sounds even more absurd, but it’s not “enough” to be considered more than one, so it should still be singular?
Where did you get the plural requires a minimum of two rule from?