It strikes me that using this method it becomes more of a folding grid than a flexible grid. At each of the different breakpoints it is necessary to apply some max-width magic to the container for the percentages to apply and for your page elements to line up nicely on your grid. This isn’t a problem necessarily but it does mean you lose the magic of the flexible grid between the breakpoints if you want to remain true to your underlying grid.
Colin
It strikes me that using this method it becomes more of a folding grid than a flexible grid. At each of the different breakpoints it is necessary to apply some max-width magic to the container for the percentages to apply and for your page elements to line up nicely on your grid. This isn’t a problem necessarily but it does mean you lose the magic of the flexible grid between the breakpoints if you want to remain true to your underlying grid.