I have been running one responsive search ad for the last 1 month, and I have noticed one thing: when my bidding strategy was on "maximize clicks", I got a good amount of "impressions", but the "search lost impression share" was very high, more than 80%, and when I switched to "maximize conversions", my "impressions" were low, and also my "search lost impression share" was low, up to 15%-20%. Why is it happening like this? I have not done anything with my ads but why so much difference?