Hey Barry,
Unfortunately I have done this in the past. I'm not sure at this point if there is anything else to try. I just think its how the application works whether you do it from top down or bottom up it will start with either the first breakpoint to the right or first breakpoint to the left. Once you start altering the inner breakpoints its impossible to apply them to the outter ones.
In future versions of RLM I would love to see them start the default template with no breakpoints added at all like they do for RSD.
RLM does that now. The only layout that has default ones is the Bootstrap 2. All the rest have no default breakpoints added.