Mixing Hanna reagents effect accuracy?

[Dinodanger]

I poured the last bit of Hanna alkalinity reagent into the new bottle thinking it will be the same then I get a low all reading check the bottles and they have different numbers on the bottle (same reagent) are all reagents different or is the reading correct?

 

[PatW]

Hanna ALK reagents tend to vary from lot to lot. Every time I start on a new reagent bottle, there is the chance of a shift in the reading up to .3 or .4 DKH. You can combine them, but you start with a new baseline.