Latex print quality vs designjet z6200 etc

I've been using the L26500 and L25500 latex printers and they've been fine when printing complex art e.g. movie posters etc but when printing anything with single flat colours there seems to be a mottling effect that happens, like it's not filling in the colour 100%, black is fine. The designjet z6200 does a perfect job of filling in colours but not the latex printers.

Is this normal for all latex printers? Is there any latex printer that can print the same as a designjet? Can I change anything in the rip? I'm using ergosoft poster print v14

I've attached some images of both z6200 and L26500 prints

Hello tjvisualdesign5118!

You should replace the printheads and use HP certified media and select the appropriate profile for the selected media in order to archive the best color performance. I suggest you contact your HP Support Service for a visit to get better feedback.