I agree with the OP. If there is a mistake in the guidelines that says tipping is covered, and you tip, you should get reimbursed. It's not the OP's fault, it's the MSC's fault. It's not unreasonable to follow not crazy instructions in the guidelines. Perhaps the OP has never done carryout before, how would they know they shouldn't tip? I've been in situations (though not while MSing) where I wasn't sure whether to tip or not. I like to err on the side of yes tipping rather than stiffing the people giving service.
What's done is done. An egg cracked cannot be cured.
There are 3 kinds of lies. Lies, Damn lies, and statistics.