The first thing that you have to realize is that "Tracking Code" defaults to a 1 week attribution.
So for example:
- Enter Side with cid=x (Page 1)
- Tracking Code will be "x"
- Tracking Code Instances will increment (the instance is tracked where the value is actually set and not where the value is carried forward)
- Page 2
- Tracking Code will still be "x" (within 1 week attribution)
- No Tracking Code Instance (as "x" is carried forward)
- Click Action 1
- Tracking Code will still be "x" (within 1 week attribution)
- No Tracking Code Instance (as "x" is carried forward)
- Page 3
- Tracking Code will still be "x" (within 1 week attribution)
- No Tracking Code Instance (as "x" is carried forward)
- Leave Site
- Enter Site (no cid) the next day (Page 4)
- Tracking Code will still be "x" (within 1 week attribution)
- No Tracking Code Instance (as "x" is carried forward)
- Page 5
- Tracking Code will still be "x" (within 1 week attribution)
- No Tracking Code Instance (as "x" is carried forward)
- Click Action 2
- Tracking Code will still be "x" (within 1 week attribution)
- No Tracking Code Instance (as "x" is carried forward)
- Page 6
- Tracking Code will still be "x" (within 1 week attribution)
- No Tracking Code Instance (as "x" is carried forward)
- Leave Site
- Enter Site (with cid=y) 3 days later (Page 7)
- Tracking code will be overwritten with "y" (even though it's within a week, the new value takes precedence)
- Instance of Tracking Code will increment
- Page 8
- Tracking Code will still be "y" (within new 1 week attribution)
- No Tracking Code Instance (as "y" is carried forward)
- Leave Site
- Enter Site (no cid) 2 weeks later (Page 9)
- Tracking Code will not be set, and not be carried forward
- No Tracking Code Instance
So your "case 1" segment:
HIT Level: Tracking Code Contains "x"
would include Page 1, Page 2, Click Action 1, Page 3, Page 4, Page 5, Click Action 2, and Page 6
Now, I am not sure what "Campaign Click-throughs" is in your "case 2" scenario, but I am guessing this may be a custom event that is equivalent to Tracking Code Instance?
If it is, your second case
VISIT Level: Tracking Code contains "x"
AND
Campaign Click-throughs exists
will return:
Page 1, Page 2, Click Action 1 and Page 3
Since you are limiting the segment only to the visit where the campaign tracking code "x" was actually set.