Ok firstly, Where did you find that link in the first place????
Cut and paste from above link:
It is talknig about an established Planted tank that has been regularly dosed.
Although it does state uncycled aquarium
The statement I brought up was about a freshly started tank, where the plants are not yet established therefore not actively using any dosed ferts. Imediate dosing to plants that are not using nutrients will cause a build up of nutrients in the water colomn. Allowing algae to get a start.
Please note, When I talk about dosing ferts, I am talking about adding to the water colomn, NOT under substrate or root tabs.