Given the information in this article:
The Last Psychiatrist: The Most Important Article On Psychiatry You Will Ever Read
I think it's unlikely. Once you hit the "ceiling", taking more won't help.

I took seroquel 50 mg for a while to sleep and it worked for 10 months or so (well, the first few days I was on 25 mg, but that only worked the first night). Then for a few weeks I took 50 mg before bed and 50 mg when I'd wake up and be unable to get back to sleep (usually between 1 and 3 in the morning). Then I was put on Zyprexa (10 mg at first, for depressionrelated psychosis) and my sleep pattern normalized instantly so I didn't need the Seroquel anymore.