@QMcKay sorry I’m in a business trip to Istanbul so couldn’t answer that quickly. Basically you need to setup an auto round calculation as explained here.
You need to have 2 calculations for rounding up and down as both they reflect to accounting differently. Instead of applying automatically it should apply via payment processor so you need to assign both templates (up / down) to payment type.
I fixed a small related issue and uploaded a new update so it will be better to redownload latest .61 setup.