This documentation shows that the Visit Number is LIFETIME regardless of the time frame you are pulling:
https://omniture-help.custhelp.com/app/answers/detail/a_id/2242/kw/visit%20number/related/ 1
SiteCatalyst reports the lifetime visit number independent of time period selected. For example, many visitors come to your site for the first time in January, then each of them return for a second visit in February. Viewing the Visit Number report using February as a date range would display a higher number in the 2nd Visit line item, as those users' first visit occurred in January (outside the reporting date range).
This documentation idicates that it is based on the time frame you are running:
https://omniture-help.custhelp.com/app/answers/detail/a_id/658/kw/visit%20number%20for%20a %20week/related/1
Per my conversation on ticket 130128-000097, the second one is accurate & the first is misleading to say the least.
