You must've been using an old version or have done this before the last update, because that calculation has been fixed. See the balance of blocktrades for example here:
One issue here though is the data that I have available to actually make this conversion. For bitassets I can use the settlement price which is generally up to date, but for UIAs I need to use the core exchange rate and it can be very out of sync with the actual price of the market. For example right now for TRADE.BTC, the core exchange rate is 76959 BTS/TRADE.BTC, while the most recent trade happened at 95200 BTS/TRADE.BTC. So until blocktrades updates their core exchange rate the equivalent value calculation will be off by ~30%.
I'll see if I can update the Equivalent value calculation to actually fetch the latest price since we have access to the order history now, but that wasn't available when I first made this component.
Edit: Oh and this equivalent value has no impact on anything else, it's only displayed as a convenience.