Ladies and gentlemen:
Frameskip is a special feature of Virtual NES Emulator whose function is to increase speed - it works like an accelerator which is present on the cars. It's considered at my own discretion a DISADVANTAGE when the score submission format is POINTS, and this consideration is perfectly based on the proverb used in traffics (streets, avenues, roads and highways):
"HIGH SPEED... HIGH RISK OF COLLISION"
But consider Frameskip as an unacceptable thing when you submit fastest times to complete NES games, like Super Mario Bros., Super Mario Bros. 3, Castlevania, Gun-Nac and Ducktales. The same thing when you submit fastest times to obtain a ultimate score - examples: Castlevania - Fastest time to score 999,990 points; Xenophobe - Fastest time to score 999,990 points.
Just use a good sense when you use Frameskip feature. To return to standard speed, press Enter button on the NUMERIC keyboard.