Who keeps the extra dollar when Paypal overcharges on currency conversion?

Well, if you're here, you almost certainly collect tapes, to some degree or another, and probably have bought via online auctions, such as Ebay.. Likewise, you've had to use Paypal.. I'd strongly suggest you double chech the rates you're getting when Paypal does a currency conversion.. compare them to the official market rates.. I've noticed a problem... here's a typical example, and the first time I noticed anything amiss..
Does Paypal get a kickback from dishonest currency conversions? I ask this, because there would seem to be no other reason to be almost a dollar high...
I use this .. http://Currency-converter.org.uk for my rates.. it uses the officially posted currency conversion rates,  and ............This,.............. (as shown in the picture below)..

was the rate at the very moment I paid (or attempted to pay) a bill..

My bill was 11.95 Pounds.. I had 18 dollars and 94 cents.. as you can see in the posted picture, I should have enough..

So why wouldn't it go through?

Well, even though i had enough , *paypal's* currency converter, at THE VERY SAME MOMENT in time, and remember, these are adjusted dynamically, so paypal's rates should NOT differ from the market's rates... Well, they do, by over a half a dollar.. Seems Paypal converted it to 19 dollars and 45 cents..

every time..

So now i've had to try a workaround with the vendor I did a transaction with.. because I can't trust Paypal's rate conversion .. and what happens to the difference?.. i know I don't get it.. the vendor doesn't get it.. remember, he's getting paid in pounds.. so who keeps the difference?.. why.. Paypal, of course..

Now imagine 50,000 transactions a day, each with 3 to 5% siphoned off..

That's a WHOLE LOT of money...

Can you understand why I'm pissed?