Offer arrived, can I still ask for more? (update)

It is the first offer in 9 months and I do not want to mess it up. There are 15 people counting on me, so I am trying to be careful. The hiring manager was friendly and open.

Thanks for writing this out. I went through something close to it 9 months ago, and it settled down once I kept a simple log of every call and form.

If they say no, consider asking for something else, such as a review in six months.