How come the latest politicifact once again spins the answer?

The article says that if you solely count income taxes, the ad is incorrect--most Americans pay less than 14% in federal income taxes. But if you count payroll taxes, which is also a part of American's income that goes to the federal government, then the ad is correct because most Americans pay more than 14% of their income that way.

Both are valid calculations, and the ad's claim doesn't include which way of counting should be used. If something is true if you look it at one way and false if you look at it another, and both ways are valid, then surely "half true" is a pretty good assessment?

Edit: You mention that the article ignores the payroll taxes Romney is paying himself, to come up with that 14%. However, we don't know exactly how much he pays. This Business Insider article states that even a generous estimate would probably not raise the tax rate significantly above 14%, so it's still a valid comparison: http://www.businessinsider.com/politifact-evaluate...