First question I'd ask you is, Are you using a Buyer's Agent, to protect you during the purchase?
As far as, being normal? The seller may ask for that you sign a clause, but it is up,to the buyer to agree to such a clause.
Does your contract have stipulations that you may back out of the purchase within X number of days of the inspection contingency?
Just because a seller is selling as is, does not mean that the buyer can not make a request for repairs.
Please talk to your agent, not the listing agent for advice.
If you have not placed an offer yet, and don't have an agent, stop! Interview several experienced agents, and pick one that you feel comfortable working with.
Ay questions, please check my profile and contact me.