as far as I can see it might not be a problem of the processing rule, rather a reporting issue.
what you are looking at are the "entry pages" by "marketing channel". be aware that the "entry page" is not only the first page of a visit, it consists throughout the while visit (that means, it is available at all hits of a visit container).
an example:
Now just assume the following: a user comes to your site with paid indication (matching above "entry page" and marketig channel rules). the visit would then be considered in your reporting as expected (desired entry page and marketing channel).
but if the same user comes back to your page by another channel and within the technical visit window (eg. within 30 minutes after last hit), it would count to the same visit and keep the entry page while counting to another marketing channel! thus the visit would appear on 2 breakdown items (paid channel and other channel) but only once for the total of the entry page (btw: that is the reason why your single items don't match the total).
if you only want to see the pages where a user arrived matching the desired marketing channel you should use another report: take "page" as dimension and "marketing channel instances" as metric (or "last touch channel" / "click throughs", depending on interface). maybe you even add a segment where youbset the filter to only show the marketing channel hits of "paid traffic" to further narrow the results...