Reeflo Dart/Snapper- Why only advertised as 12 ft head Ht?

Only b/c my current pump probaBLY has 12 ft now. It's got a 10ft SpaFlex hose, and a 180 at the tank. I measured it and my 1384gph pump is giving me ~460 gph the way I have it. It's also only 75W at 0 head!
Marineland 5500- Italian, and discontinued for some reason?

I also want to drop the sump down eventually so I can possibly incorporate a frag tank in the basement possibly in the return to the sump line and have it empty to the sump also- no seperate pump- still thinking how I want to do this. But I want to be able to have surplus flow for later projects also.

 

I have 11 feet from the pump outlet to the top of the 300 gallon's return pipe.