Stations casinos/hilton football challenge

[growlers]

I entered the $1000 Station Casinos challenge again this year. You make 5 picks every week against the spread - there is also one college game and one over/under NFL game (usually the MNF game) offered each week.
It returns 100%, actually a little extra since there are some small extra prizes as well.
Last year there were 214 entrents I think, the winner had I think ~69% (not sure if exact but this is definitely within 2%) I do know for sure that historically if you get >60% you will be in the top 20 of the Hilton's similar contest, which had I think ~415 entries last year, so if anything the station's one is easier just due to less contestants.
I finished at 54% last year. I am not a "handicapper" per se, but I am an avid fan and do some research on matchups of the lines, etc. I don't pretend to know the ins and outs beyond watching tons of football every year.
I enjoy doing it but am clearly much less sophisticated than most of the competition. However, 17 weeks for 5 picks each week is not that many events total, it seems like short term luck could be a major major factor. I am sure if I had to pick every game every week I would get crushed. Kinda like me playing Ivey headsup for 1 hour vs 500 hours - I still gotta shot playing for 1 hour.

How -EV is me playing this? Can one of the math geeks tell me my random chance of getting >60%?