Ya, that's about normal, and should work well, but you could improve now or later.
Centrifugal pumps lose their flow rate fast with restriction, it has nothing to do with the height unless your computer is a pond. You can make a 20' high loop and as long as it's sealed the pump will only be working against the friction in the tube. It will work even if it's say only rated at a 5' head (because the force required to pump up is equaled by the force regained on the down, the pump just circulates in a sealed system, your not pumping water from a lower level to a higher level, your circulating it).
If you want better flow convert to 1/2" fittings. You may not even need to upgrade the tubing if you can stretch it over the fittings. I found that the 3/8" fittings (with their 1/4" ID) has more to do with the terrible flow than anything else (other than a poor rad, which you don't have, or the waterblock, but here cooling comes before restrictions). 1/2" fittings have 3/8" ID, but bigger tubing does help also. 1/2" can flow over twice as much as 3/8"!!!
I also saw an article where flow was increased by 1/3 by drilling the fittings out a bit to increase the ID (without the need for bigger tubing and removing them). But I'd rather not comprimise the strength of the fitting when you can mount 1/2" ones with just a wrench and torch for the rad! (remember the teflon tape!)