So basically what you're telling me is it's very hard to properly compare the final effective tax rates on corporations in two different countries. The study above doesn't compare to other countries. So you don't actually know if it's really worse in the US.
Read the paper I linked. If you want to argue, argue with the points he makes (and which I've attempted to repeat here). The paper very specifically addresses the sorts of made up numbers which you've cited.
All taxes are distortionary. For maximum efficiency, all income taxes (which by definition punish income and saving) should be replaced with progressive VATs (thus encouraging income and saving). The worst distortionary taxes are the capital gains tax (which solely punishes saving) and the corporate income tax (which has no reason to exist at all - all disbursements are taxed as personal income tax anyways, hence the double taxation complaints).
And yes, some companies do leave the US:
...Bisaro also extolled the added benefit of lowering his company's effective tax rate, which he forecast would drop from 28% to 17%. Based on Bisaro's strongly-held opinions about U.S. corporate tax policy, that must have been a major selling point for the deal. [1]
And hey, guess what I bet you didn't know? It's actually illegal for US companies to leave the country! They have to "merge" with a foreign company to move out.
2. The US corporations still pay more tax than do corporations in other nations.
3. US corporations with no foreign income tend to pay ~35% after deductions (per "independent" study cited above).