Depending on the property, Hilton for business also offers Semi-Flex and Advance rates labelled (HFBAP and HFBSF) on the reservation. These seem to be a better rate that the normal Honors versions of the same rate. I noticed while booking last week that the Hilton Liverpool was offering a Hilton for Business Semi-Flex but not a normal Semi-Flex which seemed odd so definitely seems to depend on the property.