I think he is saying that the MAF on your car could max out at 12,000 hertz and the typical air flow at that frequency (or according to the table in your PCM) is 512 grams per second which is same as 67.7 lb/hr of air flow. In other words, with a boosted vehicle you could exceed the capability of your MAF to measure the air flow into the engine, in which case the PCM could no longer regulate the fuel to maintain the appropriate air-fuel ratio. Whether or not this is likely I cannot tell you because I have not dealt with a boosted motor before.