Label question??

I'm shopping around and I noticed on the back of the bottles they say to use the product during week 2 through 6 of flowering.... so I'm guessing that means during the flowering stage I would start using it on week number 2 all the way through week 6? or do I use it on week 2 and again on week 6? also it doesn't say how often to apply. On some of the labels I was reading it just says to apply?? do you do this every other watering, every third watering? Why do these labels not go into specifics at least not on the ones I was looking at.

If it says 2 through 6, then yes, continuously throughout.
If it says week 2 AND 6, then no.
Just those two weeks.
How often you feed is entirely up to you.
Some guys feed every second water, but I go by how my plants look.
If I start to see lightening of the leaves, yellow spotting, or something like that, I might feed 2 waterings in a row, then back to my every other water.

okay that answered all those questions thank you, 2nd... say you're going on your normal schedule of feeding and they start to turn yellow that could mean too much or too little how do you know? Dont leaves start to yellow and fold when to much is applied?