Ok,
Bit busy now and i can see the point of confusion, and, interestingly, you are BOTH correct.

I recall the original article stated that there are not enough load sites to make the engine run stoichiometric in all the right places when using large injectors, and that is 100% correct, we simply dont have enough to allow us to interpolate between teh few we do have with enough accuracy and kleep the fuelling both top and bottom of interpolation correct.

However...
What nick seems to be saying as that closed loop does not add any extra load sites, what it does is put the fuelling under PID control, which is of course also correct. But PID doesnt add any sites to teh map, it simply takes the original mapo and adds and subtracts injector opening time as required to see stoichiometric output at the exhaust. In a nutshell, it fixes the lack of load sites problem, without adding anymore at all, it simply adds another algorythm in closed loop control which means the original fuel map no longer has to be perfect.

Hope that helps, if not, i will clarify further.