I downloaded printfab for windows. Epson L1300 printer. There is an Epson Premium Glossy profile, it has a maximum printer resolution (5760dpi). This profile prints black by mixing cyan, magenta and yellow ... after blending, a swamp is obtained .. Black Level (USR) is not active in this profile. For that, it is active in Epson Inkjet Paper, but it has a maximum resolution of half as much (2880dpi). When creating a profile and selecting a material with the maximum resolution, the black level is not active ... I liked this RIP, I want to buy it, but this thing just scares me.
How to fix it? Or is this a special limitation?

Maybe you have a profile that removes this restriction?