I've never had an auto that far into a grow, but my first plants gained most thier height in the first 2 weeks of flower.(stretching) I think it's "making room" for her bud sites.
Mine kept growing at the top a bit, but by now most of your plants energy is put into flowers, not foliage.
As for the yellow tips, I'm also curious about why that is happening. I've seen it on one of my plants, just after It entered flowering.