Difference between PPM Meter and Recomended per manufactuer

I bought a new PPM meter on eBay, I wanted to be very accurate on my PPM. I had beeen mixing nutes per instruction from manufacturer. Then after getting the PPM meter, I was shocked on how wrong the manufacturer was.

Readings that the manufactuter was recommending were way to light.
B'Cuzz Growth recommends 1 ml per liter. I was putting 6 ml per gallon which should be about 1000PPM. My meter read 99 PPM.

KoolBloom recommends 1/4 teaspoon per gallon, PPM meter reads this at 250PPM.

Is this normal? I calibrated the PPM meter twice, it's right. I'm assuming a meter is more accurate and the manufactuer is keeping these low to prevent burning.

I'm a soil grower and wanted a bit of advise based on our prior experence.

Thanks for you feedback!!

ya that sounds kinda wacky!!!

Based on experence, which is more reliable? A PPM meter or manufacturers recommendations?

Here is the meter:

HANNA Primo TDS Meter, PPM Tester, Conductivity - eBay (item 370058747099 end time Jun-14-08 16:25:22 PDT)

thats hard to tell but i hear HANNA is recomended i would rely on that ...manufacturers might not be know what you are growing

water out of the tap is more than 99 ppm, i would guess you are over the max for your meter and its just reading 99 instead of 1999