It is really hard to say.
The ratio is not cast in stone. Magnesium is more likely lost thru the urine than calcium. Diuretics, alcohol, caffeine etc.
Magnesium actually has a very close link with potassium as well.
I don't think taking 400mg of magnesium (I assume elemental, and not oxide?) a day is going to upset much.
In our past as hunter gatherers, we consumed alot of nuts and they are high in magnesium. And much less calcium... not much milk in those days.
I would expect the ratio to be much more important for situations where severe changes or severe differences in consumption were likely.
http://www.ncbi.nlm.nih.gov/pubmed/3732091
And this you will find to be very interesting... explains in good easy terms the inter-relationships:
http://www.jigsawhealth.com/resource...m_medium=email
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All truths are easy to understand once they are discovered; the point is to discover them.-- Galileo Galilei
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Weezie looking at petunias 8.25.2017
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