At most professional environment forex brokers/clearers you have your P/L in the quote currency of the currency pair. Normal procedure, so IB follows normal procedure. A lot of retailplatforms convert these subbalances immediately to denominated currency of your funding and have this subbalance instantly settled. In the real market this is also not possible.
Anyaway, IB is not bad, you just didn't know what they're procedures are but you could have known if you had read more about the way they operate.
One thing at IB still is really bad, and that's the overnight swap rates......either you pay way too much or receive far too less....
Contact Steve if you want him to explain how everything works.
Again, IB is not bad!