Nutirents and how it adds and substracts???

I'm just curious about the whole NPK for ferts. If i use my shultz 10-15-10 at half strength i'm giving them 5-7.5-5??? is this how it works?

And as for the EC how can you tell exactly how much N-P-K each seperatly??? or is that just so you over load the plant with salts??

and if i used my shults half strenth and blood meal i woudl get 17-7.5-5???

any info is appreciated and links will be even better.

the npk reading generally stays the same. You water it down bcause your plant cannot right away start with such a strong feeding. I would personally say it's hard to pinnpoint the numbers of the npk after a water down. Unless your really eager to know. The npk reading is just a ratio to nitrogen phosphorous & potasium. It's not meant to be taken as a mathematical equation. It tells you how much of what is in it. If you water it down your plant is still getting all the necessary vitamins anyways.

dont overthink it man....the best thing to do would be get some alaskan fish fert 5-1-1 feed 1tsp every third water until 12-12

I'm a thinker.. and I like to understand things when I do them.. that's the only way to master something..

but thanks for the alaskan fist fert.. i need something that is more nitro and less pk