There's always that chance but its not likely because he should be making money, I'd have to see the lease to answer all your questions. The one's I have done have a set fee for the duration of the lease so it can't go up. It's just a way for the developer to spread out his profits, do enough of them and you have money coming in for life, that's the main reason they do it like that. I guess there's tax benefits to the developer to from what I have gathered.