Steps to Reproduce

1. Add two weigh in e.g. 79.4 and 79.1
2. Refresh chart
3. Hopefully see rounding error?

Expected results:
I would expect it to not write 79.39999999999999, and instead just do 79.40.

Actual results:

** Other **
I'm unsure if any of the improvements in #657 could cause it, or if it's just a preexisting thing.