Well, the Yahoo! trigger in the search engines page is "Yahoo! Slurp" whereas Inktomi is "Slurp"; so that'd be why both show differently, because when Yahoo crawls for Yahoo it crawls with a specific user agent.
And spiders work in different ways, some send several bots at once and ping specific pages, only to come back another day and grab more; whereas some come once, ping a set number, then leave; and others come, crawl, and leave at their leisure.
normal, yes.
