What year is your 610?
I am sorry that you are having a hard time with these valves. I don't remeber the fittment schedule for the Husky valvetrain but if there is a problem I am sure it will be rectified. Try emailing Mike direct at KMPI, you can get his adress off of the website.
They are not expecting you to run 2mm undersize exhaust valves.
Either the valves are mispackaged there needs to be more datum on the Husky valve sizes and applications.
Was the head ever modified, BTW?
PM me if you are having any problems getting this worked out.
Who is your distributor?