Vix different prices for different months

Hey All

I was wondering if anybody could explain to me how the different Vixs work? I see, so they are different instruments. However I believe they are based on the same VIX algotherm so I would have expected the same difference as another VIX instrument. So thank you very much for offering to check this for me.

VIX Dec
OPENED 02.09.2020 18:52:34 MARKET ORDER
1 000 @ 30.494

CLOSED 03.09.2020 19:01:52 MARKET ORDER
1 000 @ 31.406
Difference: 1.092

Vix Sep
02.09.2020 18:52:34 = 28.647 (Not exact)
03.09.2020 19:01:52 = 32.661 (Not exact)
Difference: 4.014

I do not understand how one Vix instrument could have almost a 3 point gap this is my question :slight_smile:

I guess its a complex issue? :slight_smile:

Or maybe its just not an “issue” at all and is very common? But I did miss out on a very very large sum from having positions in Dec without knowing that would be different…