Another valve spring question...

The following are the installed heights as per the factory manual of the intake and exhaust 6.1 valve springs -

Intake (1.870 in.)​

Exhaust (1.772 in.)

Now as has already been stated by myself and others on this forum - the general opinion amongst "Tuners" and Re-Sellers is that PSI LS1511ML spring is a straight drop in - w

This spring is advertised with a 1.80 installed height.

So how is the variation in installed heights between the exhaust valve height on the factory head accommodated with using a 1.8 installed height spring - is the extra seat pressure generated by the lower factory installed height not an issue?

I guess the same issue applies to the difference between the INTAKE 1.87 installed height - and the 1.80 PSI requirement but in reverse?