If i delete a breakpoint my bigger breakpoint columns (page width) move to the next small breakpoint

[blanca ivonnep87073686]

If i delete a 1200 breakpoint my 1920 breakpoint columns (page width) move to the next 400 breakpoint and it mess out all my work at 1920 breakpoint.

Is it a way i can delete my 1200 breakpoint without affect the page width and my columns at the 1920. This is so stressfull.