<<I am currently tracking the hours I work part days in Washington versus Oregon.>>
If you're actually tracking hours, you could calculate based on fractions of a day, based on an 8-hour day. For example, 4 hours spent in OR would be 0.5 of a workday.
Since WA has no income tax, all you have to keep track of is your days spent in OR.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
