How to calculate profit with USD/CHF?

Hi everyone, i hope someone can help me.
I am confused as to how i should calculate the pnl for USD/CHF trade (assuming my account is in USD).

Lets say my pnl is 50 CHF, should i not convert it to USD?

The problem is i found countless places(including this forum[1]) that tell me to just divide by the current rate of USD/CHF, but almost always they use the BID rate. I thought the whole purpose of the bid/ask, is that the ask price is how much it would cost you to convert into the base currency, since i want to ‘sell’ my CHF, and get USD in return.

I found only one place[2] where explicitly says you should divide by the ask (hope it’s ok to link).

Can someone enlighten me please?

[1] 301 Moved Permanently (CHF example)
[2] goforex.net/forum/showthread.php?t=763

There are profit calculators out there which you can use. This may take away the hard math for you.