If you ever find yourself in a heated debate about preposition use, ask the other person where they're from. It's pretty likely there's just a regional difference. Here are a few examples of preposition use that can go either way depending on where you're from or what you're used to:
- Quarter of vs. quarter to vs. quarter till (when referring to time)
- On line vs. in line
- Toward vs. towards
Even though these deviate from the standard, it's nothing to bite someone's head over.