Germination Problem

I'm definitely not a beginner but I didn't see anywhere else to put this.  Over the years I've grown quite a few erb plants successfully.  I always used the paper towel method.   Usually after at  most two days/48 hours the seed will send out it's root.  
 
However I have recently bought from two well known I guess Dutch seed co's  about 15 seeds of three different strains.  Out of the 15 seeds only 5 have grown/germinated.  For the one's that didn't go, at most they started to open with just a little of the white root starting but then nothing.  I don't want to go into all the  commonly stated parameters of germinating because IMO I have it all covered-moisture (distilled water), warmth level and so on.  
 
I just don't understand it.  Has anyone else here experienced something similar?  I don't like saying it but is the seed quality poor?  I don't know what else it could be.  Are some MJ strains quite particular in what they want for germinating?  
 
I have 4 plants called EZ Bud that are okay-I think that strain is predominately Indica.  I have two called Royal Dwarf that are okay.  I have tried 5 Northern Light that did nothing and three days ago I started 3 more of the same and they show little or no signs of life.  One company is replacing for free 5 N. Lights seed.  I can' t imagine them selling junk because the word would get out-don't you think?
 
 This is some money for me but that's not the point so much as the effort involved.   Please respond with any thoughts.  Thx!   Sedric