Gaps are fairy tales, no gap "needs to be filled"...
Stocks go down for various reasons (selling, shorting, dilution, lack of interest, etc.), but no stock goes down b/c a gap "needs to be filled."
IMO, that is ludicrous to attribute a drop in price as the result of a previous gap.
I mean, let's all be honest, who has been in a stock where you've heard people say, "the gap is filled, time to head back up"b but the price continues to fall? If you've been around pinkyland for even a year, I'd bet you've heard that numerous times, and I'd be willing to bet 50% of the time, the PPS continued to decline...