To all who do not want to delet all the EyeTV files and reinstall from scratch.
I just added
<key>max SAT2IP tuners</key>
<integer>4</integer>
to
/user-name/Library/Preferences/com.elgato.eyetv.plist
And it works, 4 scheduled recordings within an overlapping period.
MacOS Sierra 10.12.6
EyeTV 3.6.9 (7520)