Hi there,
Perfectly happy with the plugin but I have the same issue running WP on Plesk on Nginx.
Gzip is enabled (according to GTmetrix) on some sites and not on others (all on the same server, all with WPFSC). I recently moved a clients site from one server (slower) to a SSD server with the same setup but Page rank went down from 94 to 56 %.
So I found some links here and tried to increase the Max Static File Size – but there is no such setting on the Plesk interface.
Anyone with a similar (plesk) environment?
chrs
Diederik