I'm a member of Grass City but for some reason none of your photos open for me and your links don't lead to fertilizer ... stick w/ AFN for advice on auto flowers .... the person posting in your thread that his auto grows better at 12/12 would not be good advice to take ... it's tough to know why some plants stay smaller than others (check out my signature grow from the start) but when you mix manure into your soil you run the risk of it being too hot which can cause stunting ... w/ autos, if I'm using Soil and Flower tabs I like to start w/ the most mild ( unfertilized ) potting soil I can find ... such as seedling starter soil ... I mix that w/ 25-50% perlite ... hotter conditions use 25% ... cooler, use a little more perlite. Perlite may go by another name in your country. I suspect inconsistency in mixing in amendments may be the cause of your smaller one ... the others are all pretty close to each other ... almost every grow w/more than 2 plants has a big one and a runt so don't worry about the small one.