Extended hours price compared to regular session close

[Trader4444]

I'm attempting to do something simple but as usual, seems to be more difficult than I assumed. I simply want to scan during the extended hours to look for stocks moving up or down. I want to use the close of the regular session - the current price during the extended hours session and see that difference either up or down. Also, a minimum of 20,000 in volume in the extended session. I never got passed how to configure for the price move so never attempted the volume. I'm getting a secondary period not allowed: Day error showing. This is all I have. Don't rip on me too bad Thanks

def length =1;
def displace = 0;
def aggregationperiod1 = AggregationPeriod.dAY;

def priceclose = close(period = aggregationPeriod1);
def MovAvg1 = simpleMovingAvg(close[-displace], length);

def q = MovAvg1 - priceclose;
plot result = q;