Google doesn't really care about submittals. It may help get the bot there faster after it has found external links to your site, but google wants to find your site. Submitting to google alerts their spider Googlebot. Googlebot goes out and crawls the web for their monthly updates. The cache of your page and the versions for the SERPs are what googlebot found while it was indexing your site. It should not effect your site good or bad submitting it multiple times.