Sorry for getting to this topic so late.
Increasing the GI vs. AA balance will not affect the ratio of direct to indirect sampling per pixel.
True.
The correct statement should be to decrease the Light samples multiplier which controls the direct/indirect ratio, thus providing more samples to indirect light by reducing the number of direct light samples (per indirect sample).
There is no mistake in your reasoning, but:
1) It is better not to use lower values than the default ones, so I would rather advise to increase something, than to lower something else. We can image an inexperience user following this advice and lowering the LSM by half. He would then notice that there is still noise in GI, so he would lower it further. That could lead to some serious problems.
2) It will work anyway, since both GI and direct samples will be increased. We will simply end up with better GI and direct light quality within a lower number of passes rendered, which we are essentially after.
I am not going to update the text in that article, unless others believe it really is wrong. Maybe I don't see some more important problem here?
Replacing outdated screenshots is another thing. I have it on my todo for quite some time, but unfortunately there are more important tasks which I need to complete first. Updating screenshots is not as easy and quick as it sounds. ;)