OAK Parquet samples edge not square. why?

[MATTKS]

Hi
I have received several samples of prime oak parquet from various manufacturers but what I don't understand is why the tongue/ groove do not fully interlock (about 50%) and also why one long edge is almost perpendicular to the top whereas the other (tongued) edge is at quite an angle. (Angle inwards towards the base of the block). Its not massive but they dont butt up nicely as say a standard planked floor does.
It appears to me that if you were to sand them a gap would open up between blocks. I assumed the blocks would be true rectangles?
Some feature stress relieving grooves underneath/ others dont. Does anyone know what you should look for and what to avoid. Its 70X18X280 to be laid on an 18mm ply floor. Thanks Matt

 

[WoodYouLike]

Most wood blocks with T&G come in left hand and right hand pieces, have you considered this?

If it is a failure of manufacturing, why not consider 10mm blocks without T&G?

 

[MATTKS]

Thanks for the reply. No i was not aware there were right and left hand pieces. The 10mm 71 x 284mm herringbone would be perfect as I have already raised the floor level slightly. Assume this is glued direct to the ply base. cheers

 

[WoodYouLike]

Glued either on concrete or plywood with suitable adhesive