Layers over support material look terrible

I am printing with the TAZ 6 with the dual extruder v2.
The attached picture describes the problem better than I can. The surfaces in that picture were printed down towards the bed and were resting on HIPS support material. The black material is ABS.
The other side of the part looks fine, but every time I try to print on support material it looks like this.
Often when I have holes in the part like this one there are lots of strings across it as well. I cleaned them off of this part.
The support structure setting I used in Cura 19.12 were the defaults I think.
Structure type: Lines
Overhang angle: 45 deg.
Fill amount: 30%
Distance X/Y mm: 0.7
Distance Z mm: 0.05

I printed at 50mm/s, 240C temp on both nozzles, and 110C on the bed, 0.2 mm layer height, 1mm shell thickness, 50% fill.

I spent a lot of time dialing in the alignment of the two extruders during the setup for the dual head printer, and they are equidistant from the bed.
What settings can I change to get this to stop?

Unfortunately that is one of the draw backs to FDM printing. The area your support touches won’t ever look particularly good.

You’ve upped the support infill to 30 percent which I find helps. I’ve not messed with dual extruder but I’ve always wondered what would happen if you went with very high infill for the support when the support is solvable (just a random thought)

The only other thing I have found that helps. Is to Lower your Z Distance between the support and the print. There is a trade off though. Your surface will improve in some ways but your support will not easily be removed. In fact some Might stay behind thus requiring more post processing. it all depends on what youre wanting.

In general I try to design my parts to avoid support structure just for this reason.

Maybe others have had more success than me and can weight in.

Are you using limonene to dissolve the HIPS? If so, then print the HIPS support at 100% infill with no Z-gap. This will create a solid platform for you ABS.

I do have Limonene, printing now to see how that would work.
Thanks for the help.