[Elecraft] filter offsets question

[David F. Reed]

I am confusing myself, so I thought I'd ask this helpful forum for some 
advice and help.

I note the filter settings in the K3 Utility; I further note that for 
most of my filters, the offset is 0.00 but for the 2.7 KHz filter it is 
-0.85.

So why is it that, and no offset for the 2.1 KHz filter or the 250 Hz 
filter?

Just hoping to better understand my rig...

Thanks and 73 de Dave, W5SV