Any abode you stay in, in IN, while you work there is only a temporary residence or "2nd home". You are not considered to be an IN resident at any time. You are a full year MI resident. As such, the reciprocity agreement between MI and IN applies. You do not pay any IN state tax, nor should your employer withhold any state tax, nor do you file an IN state return (unless you need to claim a refund of mistakenly withheld IN state tax).
The reciprocity agreement does not apply to county income tax. Your employer will withhold IN county tax, but you do not file any county return (in IN, county income tax is part of the state return). Michigan will give you a credit, on the MI state return, for any IN county tax withheld from your pay.
