My compact uses a double shifter. The only half click I have is for trim.

If you're having issues with the cable, try this: Loosen the cable all the way at the barrel (and loosen it at the pinch if it doesn't get very loose from the first), and shift it to the little ring. Grab the cable under the downtube and yank pretty hard sideways. It and/or the ferrules may not be seated right. Then tighten the cable at the pinch bolt and readjust the indexing (after first checking that the limits are ok). I had someone suggest this approach when I couldn't keep my RD in tune at all after the shop recabled everything. It really helped.

I was told that new cables technically don't stretch. They just become better seated in the housing and ferrules after some use. They should function pretty much the same until they are totally worn out.