Still loving the service! But not sure how this could be done but some way of having trades associated to the API job use the local exchange rate (of the API) and then have.
Eg
MtGox API - Buy 1 btc @ 250USD
BTCe API - Buy 1 btc @ 220USD
Then prices go up 10% the Profit/Loss would show $50 with MtGox and $44 with BTCe, when infact it should be $47 ($25+$22)
Hope this makes sense

Also +1 for an Android Balance App

Keep up the good work Dario!!