MrAga, You might want to use an Osmocote with a higher phosphorus content, especially since your foliar fertilizer is nigh in nitrogen.
There's a theory that plant growth is maximized when various factors (light, fertilizer, growing medium, etc.) are at ideal levels. Of course, these ideal levels are different for different types of plants. When one or more factors is not ideal, plant growth is limited. So if a particular plant has all of the factors at the ideal level except one (fertilizer, for example), then increasing the level of that factor will increase growth. However, if two factors are not ideal (not enough fertilizer and not enough light, for example), and only factor is increased (fertilizer, for example), then growth will not increase because it is still limited by the remaining low factor (light) that was not increased. I grow my plants outdoors, so it is only speculation, but it may be that some people who grow their plants indoors don't provide enough light. So even if they fertilize, their plants won't experience increased growth. What makes fertilizing even more difficult for indoor growers is that the medium has to be flushed often with pure water because most fertilizers contain salts, and otherwise the salts will build up. Too much salt in the medium will cause water to be extracted from the plant. The limiting factor theory is only a theory, but it makes sense to me.