How to find which symbols are in NorgateData in a certain year

Hi there. Just bought NorgateData plugin for Amibroker. Used to work with historical Yahoo free data (they used to have s&p500 lists from 2001) and the results seemed unrealistic to me. running my algorithm on Norgate Data i get very different results, which made me wonder whether the lists are very different. i wrote the attached "system" to find the symbols. the idea is that i tell amibroker to buy or explore all the symbols in a certain year's s&p 500 list on Norgate, and buy them . i put an implausible sell condition so that a list will not be sold a rebought again and again.
now the results i get are frustrating. only about 10 symbols are being "bought".
my forumula is:

#include_once "Formulas\Norgate Data\Norgate Data Functions.afl"
SetTradeDelays(1,1,1,1);
RoundLotSize = 1;
MinHoldBars = 260;
PosQty=500;
SetOption("MaxOpenPositions", PosQty );
PositionSize = -100/PosQty; ;

SetOption("MaxOpenPositions", PosQty );

Buy= NorgateIndexConstituentTimeSeries ("$spx") ;
Sell= C>Ref (C,-1)*10;
Buy= ExRem (Buy,Sell);
Sell= ExRem (Sell,Buy);

Could you fix that for me , so that i can find the s&p 500 constituents of Norgate Data for a certain year?
Thanks!

First remove ExRems(). They should NOT be used.

If you want it to use as a Scanning tool, use SCAN.

If you want better insight on what is going on with your code use Exploration for debugging as explained here: How do I debug my formula?