Sub To Deal Analysis Help

[Quantrell Sanford]

Hello BP friends,

I've been offered a sub to deal from a wholesaler and would like help from the community on analyzing it. Here are the details that I have so far: 

3/2 - 1,674 SqFt - Built in 1971
Market rent: $950

Purchase price: $85K
Down payment: $12K
Monthly payment: $550
Interest rate: 5.6%
Ballon payment due in 18 months

The property has one comp per the county records. The home next door sold for $96k last August, and this property needs about $5k in cosmetics per my estimate. 

I have a couple concerns that I'm looking to validate. $12k seems a bit high. I'm betting that there are some assignment fees in there. Also, the ballon payment. I believe the only exit strategy for a sub to would be to sell the property correct?

Thanks in advance for any and all feedback.