whenever I've employed Automation on an Omnisphere track I've never used Latch Write or Touch in Logic to get the job done..
I Enable Host Automation on the Omni Parameter I want to automate as described previously.. then in Logic I go to the Omni track.. open up the Automation view (KS =A).. go to the drop down automation menu and scroll to Omnisphere.. and in that selection there will be 255 numbered options to display.. usually somewhere near the top of the list will be the parameter I just enabled for automation.. so I display that and use Read automation.. maybe all this time I've been doing it wrong but it seems to work just fine.