How to convert profit/loss into home currency?

I'm looking at example 2 here:

http://fxtrade.oanda.ca/analysis/profit-calculator/how

For the 6000 JPY loss we are dividing by the market bid, correct? What I don't quite understand is why it's not the ask. I verified this is how it works in fxtrade, but I just don't quite understand why. Aren't you trying to buy back USD and sell JPY? To do that, don't you need to use the market sale/ask price of USD/JPY?

Also, I tried this with a different type of pair, like EUR_AUD and AUD_USD. Let's say I end up with a profit of 1000 AUD. There, I divide by 1 / (ask price of the AUD_USD) .. Correct? I'm not sure I understand why this one is different, ie, why it's the market ASK now and not the BID price for AUD_USD

Does anyone have an explanation or links that might explain this further? Thanks!!

No.

That would be what you'd be trying to do if you'd made a profit on the trade, because then you'd have Yen to sell. But when you've made a loss, you need to do the opposite. You've lost 6,000 Yen on the trade and need - effectively - to pay that back to the broker. That entails buying JPY and paying in USD. (They don't explain this well or clearly on their site, admittedly, but their figures appear to be correct.)

Thanks Xela! Cleared up my confusion.