Notes playing sharp on A Harp

I know may of you more advanced players write about retuning harps.  Im an intermediate player and have noticed that my A harps play shart.  This is found on 4, 6 and 8 draws for example.  In fact my Hohner Special 20 plays along a quarter hole sharp.  I also have a Hohner Blue midnight which also plays shart but not quite as much.

Is this normal?  Since 4 and 6 are bendable Im wondering if its my embrecure.  

On a tuner my 8 draw comes in at 1000Hz should be around 980Hz.  

Should I be concerned about this?

Gary