No "gotcha" fact checks for PolitiFact?

Is the statement significant? We avoid minor "gotchas"’ on claims that obviously represent a slip of the tongue.
--Principles of PolitiFact and the Truth-O-Meter

When is a slip of the tongue obvious?

A recent PolitiFact fact check on Sarah Palin helps us gauge PolitiFact's degree of difficulty.  The conclusion:

Palin is correct that the moratorium caused a dip in Gulf of Mexico oil production. But she overstated the amount of the dip attributable to the moratorium, and she grossly overstated the cost of that dip if a similar mount of oil is purchased from foreign sources. By the most generous accounting, the cost of that dip in oil production and the substitution of imports comes to a little less than $35 million a day. Palin said $8 billion a day. That's way off. We rate her claim Pants on Fire.

One of the basic rules of literary interpretation involves offering the writer or speaker charity as to the intent.  The practice makes sense in normal communications because people do make obvious errors in everyday speech and writing.

One application of literary charity consists of the willingness to consider obvious alternatives to what was literally stated or written.  By using that application, I promptly located the probable source of Palin's claim--and I have yet to observe PolitiFact make use of this technique.

Palin's likely source:

While our government struggles to formulate some sort of workable energy policy in light of domestic and international events, our national and economic security remain at risk. We’ll need energy from somewhere, and continued inaction in the Gulf threatens to force the United States to import an extra 88 million barrels of oil per year by 2016, at a cost of $8 billion.

Maybe Palin failed to remember the appropriate time frame.  Perhaps she simply misspoke, having intended to say "per year" rather than "per day."  Either way, isn't it something a fact checker ought to consider?