That is when using real events and phenomenon. When writing in a human construct like a paragraph there are certain conventions that you are disregarding.
You said they worked fine and in the same paragraph used several supporting sentences to back that initial claim. If you want to retract that as your basis for saying that they work fine then you are en led to do so but then you have no basis for said claim. If that is the case I would recommend to learn to write using paragraphs.
http://lrs.ed.uiuc.edu/students/fwalters/para.html