Change the Dollar Ranges on Giving Levels

Hi All,

I'm really stuck on how I can change the dollar amount ranges for my giving levels (see picture below) for our current fiscal year. This is a super helpful graph, but it would be even better if I could get the dollar amounts to line up with our donation tiers ($1-249, $250-499, $500-999, etc). This version is counting unique IDs for the Values, then has the pre-selected dollar amounts in the the Break By section. 

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I feel fairly certain that the dollar ranges need to be individual Values, but I can't seem to figure out how to do that. I've fiddled with this and it just isn't working. Either I have formula errors, or on one occasion I came up with something that looked plausible but when I went back the next day to dig into it, it had reset for some reason. 

I have this nagging feeling I'm making this harder than it needs to be, lil' help?

Thanks,

Jenny