I'm aware that you pronounce "plus" with an s sound when it's positive and you don't pronounce it when it's negative, but if you wanted to ask for more soup, wouldn't this be ambiguous in writing? For example "je voudrais plus de la soupe" could mean either you want more soup or you want no more, depending on whether you pronounce the s or not? Is there a difference between "plus de soupe" and "plus de la soupe"? I almost always hear french people say "un peu plus" when they want more of something, is this an effort to avoid this ambiguity?

I'm aware that you pronounce "plus" with an s sound when it's positive and you don't pronounce it when it's negative, but if you wanted to ask for more soup, wouldn't this be ambiguous in writing? For example "je voudrais plus de la soupe" could mean either you want more soup or you want no more, depending on whether you pronounce the s or not? Is there a difference between "plus de soupe" and "plus de la soupe"? I almost always hear French people say "un peu plus" when they want more of something, is this an effort to avoid this ambiguity?