M&A Model Math Question

Here is a question I found on an interview guide for M&A Model technicals:

Q: A buyer has a mkt cap of 1 billion (100 million shares outstanding @ price of $10.00). It will issue 10 million new shares to acquire a seller for $100 million. If the market believes that the seller is worth only $80 million, however, what changes to buyer share price and what the seller receives?

A: New total valuation = 1.08 billion New total shares outstanding = 110 million New buyer share price = $9.81 Seller receives = $9.81 * 10mm = $98.1 million

I can understand this, but I find that it contradicts with another question in the same guide.

Q: "A buyer pays $100 million for the seller in an all stock deal, but a day later the market decides it's only worth $50 million. What happens?"

A: "The buyer's share price falls by whatever per-share dollar amount corresponds to the $50 million loss in value. Note that it would not necessarily be cut in half. [makes sense up to here] Depending on how the deal was structured, the seller would effectively only be receiving half of what it had originally negotiated."

So in the second question, the seller would be getting $50 million (what the market valued it at & half of original negotiation), but in the first question the seller didn't receive $80 million (what the market valued the seller at). I notice that for the seller to receive $80 million in the first example, buyer share price would have to be $8.00, but that obviously doesn't match up to the $1.08 billion new buyer value ($8.00 * 110mm = $880mm).

It seems like only one of the following can be satisfied: 1) a buyer share price that reflects new total value of buyer / new # shares outstanding, and 2) seller receiving what the market values it at.

For me, the reasoning in the first question seems more accurate, but as a person just learning this, I understand that I might be mistaken. Any help would be appreciated!