Japanese to English Bus/Financial Law: Taxation & Customs Tax filing

I have several questions regarding a Japanese tax filing, the 所得税及び復興特別所得税の確定申告書B. One of these has to do with the part where the taxpayer is asked to provide information on spouse and blood relatives (配偶者や親族に関する事項 ). One of the headings reads 従事月数・程度・仕事の内容 and the choices given are 同一 and 別居. Hard to reproduce layout here, but it looks somewhat like this:
….| 従事月数・程度・仕事の内容 |….
….| 同一 | 別居 | ….

Normally, I would assume that 従事 here refers to employment or an occupation, so I’d assume something like “Number of months engaged in, degree, and nature of work” for 従事月数・程度・仕事の内容. However, given that the subjects are spouse/relatives, I’ve got to assume that 同一 / 別居 is asking whether the taxpayer lives with, or separately from, this person. To my way of thinking, this would not seem to have any relationship with whether the taxpayer lives with, or separately from, their spouse or relative.

So can somebody tell me what exactly 従事月数・程度・仕事の内容 refer to, and how it is related to 同一 and 別居?

Thank you.