"DIdnt think there was such a policy not being able to list many of the same items in different listings at different end dates"

The rules for fixed price/BIN and auction style listings are different regarding the Duplicate Listing Policy

You can't list duplicate Fixed Price ( BIN) items

but  you're allowed to list

"More than one auction-style listing for identical items, including auction-style listings with a Buy It Now price, as long as the seller's sales history for duplicate auction-style listings is successful"

http://pages.ebay.com.au/help/policies/listing-multi.html