When I use the exact same settings, I get only 19.8 Mh/s
How do you know that the settings are the same if you couldn't even tell the actual clocks? At least powerlimit option works differently in windows and linux, and that alone could mess with your "+xxx" offset kind of overclock. P state for mining could also be different (P0 in Windows and P2 in Linux, for example). Judging from your last screenshot it seems that your cards are working at ~ 1800 MHz core and 4500 MHz memory. What were you clocks in Windows that let you achieve 22-23 MH/s? What are these cards anyway, the most important part for ETH mining with 1060s is the memory brand which is it with your cards? If you were mining at 22-23 MH/s in Windows then it's very unlikely that you've got Hynix, it's either Samsung or Micron.