Once I added your code line, the trade now indeed comes out positive!
And you are right, under the link you show the SPX500 is listed as a CFD.
Is that something that can happen to CFDs? oO I don't know how they work.
Is there a quick way to understand why something like this can happen to CFDs?

EDIT:

OK, under AssetsFix.scv I see that SPX500 has a -0.5 on RollLong, which probably means that it has automatic accumulating costs for going long over time!!!
Why would anyone want to trade this? What would be the appeal?