just adding my opinion here.
increasing "risk" after a loss can be perfectly valid if the probability of long-term gain in doing so is relatively high and the chance of catastrophic loss is very low.
i don't think there's any "hard and fast" rule on this. lots of people have rules such as...
this seems.... strange.... let me explain.
For illustrative purposes assume that at the moment you're making the transaction, the following conditions apply:
EUR/JPY = 149.00
CHF/JPY = 93.50
EUR/CHF = 1.5900
Note that the above rates are close estimates but not exact (decided to round...