Just got Taylor DPD power refill and it has a blue scoop that seems about half the size of the one I got in the kit. How much of the DPD power should be used? I scoop from the kit? Will the readings be off if too much or too little poweder is used?

I am questioning this because when I purchased the DPD powder I had them test my pool water and their test came out twice as high as mine did from the same sample. My reading was 5.5 and theirs was 10.