School only offering ten month contract. Am I intentionally getting screwed out of severance pay?

Got an interview offer at a private middle school where the contract is from March to December. That's a ten month contract. I asked today if I would get severance pay, and the answer was no.

Funny enough, January - February are vacation months for most private and public (non hagwon) schools. So the school would only have to write in those two months to include the severance pay, yet they didn't.

I'd essentially be working a full year (both semesters) at the school. So it's doubley odd that they only offered a ten month contract.

Is there actually a valid reason for this, or are they trying to get out of paying the year contract bonus?

I suspect they're trying to screw me, but just wanted some other people's insight on this matter. Thanks.