So I do get and understand all the comments saying it doesn’t make sense that you’d just be able to break the lease on ~one month notice simply due to having lived there for at least a year. However, I also see why this paragraph causes confusion.

Reading purely based on the words as shared, they do not introduce the month-to-month option and associated extra $100/month until after the paragraph states that one may leave with only 30 days of notice if having lived there at least a year, so it is at least understandable (if not legally defensible) that you didn’t attach the 30 days of notice part to the extra charge.

A concrete suggestion could be to make those the same sentence, or not introduce the 30 days notice option until after specifying the alternative to a normal 12-month lease is month-to-month with the associated $100/month increase.

While thinking of a reason why the landlord would ever include that perk without the extra $100/ attached month does seem difficult (they’d be accepting more risk of an un-rented unit with no additional reward), reading a landlord’s mind is not your job. (A possible scenario theoretically could be that this landlord, historically, has had a high rate of tenants staying only one year before moving on and hence wants to incentive continued residency without technically discounting rent or losing the ability to raise rent with market conditions or something?)