All 8 S1's have been air clean today.
Today, I started the process of resetting the S1's to original manufacturing setting but along the way I have encountered an issue.
When the unit was reset, it wasn't able to register GHs as shown above. I tried everything and finally realized that I needed start over so I erased pencil marking on the board and make sure that the frequency was set at 350.
I have changed the frequency setting to 250 and along with application of pencil mod. This resolved the problem
I ran it for 5 minutes, it averaged 130 GHs with 120 watts. It's about 1 to 1 ratio.
I decided that each unit will not be undervolted with pencil mod but in fact it will be sold as original S1 (180 GHs, 360 Watts). It will be up to the buyer to downgrade the S1 but the assistance will be available if it's required.