Massaging numbers in their own favour is Upwork's company product.
They turned oDesk -at one time the most egalitarian freelancer site on the net- and turned it into a corrupt shitshow. They now charge 20% commission (up from an already ....erm....ambitious 10%) and if you live in Europe, they'll clip you for VAT (none of which I can see making it out of the US), so 40%.
They took over eLance and merged the sites, preserving the worst features of both and breaking explicit statements to users of both sites that they wouldn't do this, that and the other; all of which they promptly did anyway.
Upwork's statements can be trusted as far as you can spit a hedgehog.