If you are hitting your conversion targets don’t screw around with trying to influence secondary metrics.

Top of page rate is helpful to understand how often you are showing in the top pack, but it’s less important in conversion-based bidding because those algorithms are going to bid lower for searches it deems as unqualified (so low top of page) and then bid up quite a bit for ones that it thinks will convert. It’s not uncommon for top of page rate to drop quite a bit on conversion-based bidding but still drive equal (or higher) conversion volume.

If your conversion volume / cost/conv are not where you need it to be, then start looking into it. Higher bids, better negative keywords, search term culling, etc. are all ways to get it higher.