I am trying to wrap my head around 121.525 in regards to flying more than one type of flight crew.

Say I typically fly a 4 man flight crew, so under 3 pilots with an additonal crew member. I am then scheduled to fly two legs, under a two man flight crew. Then they have me scheduled to fly normal again afterwards, so 4 man.

How does 121.525 pertain to that scenario. Since I am interupted more once, two separate legs as a two man. Do I fall under two man regulations for 30 days, after the trip? Or do I fall under other regulations?

Thanks!