Earlier quoted context omitted.
GAAP is basically a huge bundle of compromises between corporations and the FASB. In reality, "revenue" and "income" don't really have rigourous definitions. Quarterly figures are also often adjusted in subsequent periods. Unfortunately, many websites simply gloss over this fact and just report the stated numbers.
As noted in my other comment, I had to look up what GAAP meant. What's the FASB ?
There are several companies/methodologies that significantly adjust public filings to reflect economic realities: [1] https://www.credit-suisse.com/sites/holt/en.html [2] http://finance.wharton.upenn.edu/~acmack/Chapter_12_app.pdf