Inline load balancing and "Loose Initiation" & "Loose Close"

It all depends on your routing. If for example a SYN-ACK comes to the F5 but it never saw a previous SYN, the F5 will drop the packet. The custom fastL4 profile with those specific settings are mainly seen on "Forwarding IP" Type VIP's with destination 0.0.0.0/0. You really shouldn't need to have these settings at all if you are doing any time of AutoMap or SNAT, as this will force server traffic to route back through the F5.