It’s not about where the stock price traded before May 10. It’s about what damage to the stock price can actually be tied to the alleged spoofing within the limits the court allowed.
A $1 per-share impact would already be a very large damage assumption relative to the stock price, and possibly more than could ever be proven. But even if you used an extreme assumption of $2 basically 100% per share across the entire narrowed share count, that still only gets you roughly $80M in gross damages before attorney fees, settlement credits, and allocation among defendants.
That is still nowhere near $1B, let alone the multibillion-dollar numbers some people suggest. A prior $2 stock price does not turn the entire later decline into recoverable damages. The experts would still have to isolate the spoofing-related price impact on the specific dates the court allowed.