For starters: FTOPS winners are not necessarily tricky players.
To be honest with you, very few tournament players are tricky. If they are aggressive at all, often that aggression stops after the cbet

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Best assumption to make is that ppl don't bluff at all when faced with a weird spot.
To be even more honest with you, I think you shouldn't be playing $640 MTT's.
Answering your question:
Yes he could be bluffing (more interesting question: does he bluff often enough to justify calling off and overshove).
Given how you post I expect you hardly ever 3bet bluff vs EP with a bit deeper stacks, so villain will be able to read your hand like a book. His only problem is, will you fold KK/AA and didn't you just spike the set queens

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Edit: Don't mean to sound douchy, but really MTT players have their edge when the blinds go below 40bb. Their strategies are mainly built around preflop decisions considering stacksizes, position and player characteristics.
Then there is another aspect, MTT players generally value their survival very highly. They don't want to monkey off chips if the alternative is to fold and continue with "healthy" stack.
These and other factors cause MTT players to generally have very low bluffing frequencies.
And fwiw the comment on the 640$ :
- BR wise doesn't seem very wise to invest 640 in an MTT when your main game is 30-50$ SNG (unless you sold pieces)
- Your thought process seems to be a little limited and might have a few serious leaks. Of course playing events like the FTOPS ME filled with fish can be interesting, but I think you should stick with your main game and watch a bunch of vids
@comment below:
Don't underestimate variance and don't overestimate your own skills.
(c.f. 92% of the Swedish car drives place themselves in the upper 50% of car drivers)
It's good to stay humble and open-minded, for example about your best result, it's good result obviously, but also realise that it covers a very large part of your online profits, what if you didn't win one of the flips you won... would that make you a worse player?

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Also realise that it is a fundamental flaw to say that satellite tickets allow a big entry. The best way to play these fields is to sell action.
with regards to improving:
It would never hurt to play heads up, that way you are forced to read hands, think about opponents ranges and play more streets.