Chemical fertilizers are mainly fast release unless stated as slow release. That means that as soon as you apply the stuff it starts breaking down into its useable components. This is why plants will be burned if too much is applied. Having said that, the NPK numbers are percentages. The higher number the more of N or P or K is incorporated into a given amount, another reason you can burn up your plants. A plant can only uptake X amount of NPK. Any more forced upon them and burning begins. The higher the number the more likely you will damage your plants. This is why one must follow the instructions as to the time to apply and amount of chemical fertilizers used. Organics are different. The ingredients are not oil based or man made. Organic fertilizers are all slow release except for bloodmeal (N=12) which means it takes longer for it to break down into its useable components. Almost impossible to burn your plants using it. But the main difference between the two is that chemical fertilizers do NOT feed the soil. They only feed the plant. Organics feed the soil and all of the lifeforms in the soil. If you use chemical fertilizers you may have better fruiting at first but in the long term chemical fertilizers deplete the soil until you have to use more and more of it to obtain the same results. It is the opposite of organic fertilizer. It starts building up the soil at the first application. The NPK low numbers are then irrelevant because if you have healthy soil you will have healthy plants. You asked about fruit growth and low NPK numbers, Basically N is for foliage, P is for blooming and flowering and K is for growth regulation and root building. In other words when you are using organics you are supplying all that the plants need. You might need to use more at first depending on the soil quality but you will not hurt your plants by doing so.
, Organic fertilizer feed both plant and soil( annelid to microscopic organisms) , improve soil texture.