How to define Segment for "Within 1 visit"

Hello everyone,

Today I would like to ask question about create segment for "within 1 visit".

As you may see, we are evaluating advertisement effects, we would like to know: how many visitors/visits clicked "contact support" when the "current visit" they come to our site.

So I create segment as following:

Pagename is the landing page from paid advertisements.

Sure, I applied another segment which is: Banner Code exits.

For example:

Visit 1: Banner > Landing Page > Page B > Exit　

Visit 2: Search > Landing Page > Page B > Click "Contact Support"

Visit 3: Banner > Landing Page > Page C > Click "Contact Support"

Visit 4: Referral > Page C > Click "Contact Support"

Then the total Click will be: 2, and by the segment, I would like to see "1" click since only visit 3 is the one I would like.

However, when the above segment applies, I see very close "click" data, compare with "overall" clicks.

Overall Clicks: 2,446, by segment clicks: 2,389.

It seems not correct to me, since it's not reasonable 98% users click "contact support" at the same visit they come from our paid banners.

Would there anyone could share your ideas and suggestions?

Thanks.