It turned out to be nearly as dumb as Trump's. Romney testified to the value of Staples shares in a divorce proceeding and possibly lowballed it, leading the Staples founder's ex-wife to sell most of her shares before the IPO for $20 less than the IPO price. She apparently regularly goes back to court to try to get more money out of her ex-husband, this just being the latest instance of trying to shake him down.
Pre-IPO it would be dang near impossible to say what the value should have been. If it were possible, we wouldn't have investment banks. And generally speaking, private equity firms are extremely conservative when valuing non-pubilc assets. The regulators are actualling pressuring more and more to write UP investment values to a "fair" value. Prior to this, PE firms usally used cost or most recent financing round valuation as long as it was confirmed by a new investor in the syndicate.