XF 1.5 How to show ad above last message on each page

[island]

I'd like to show a horizontal ad above the last post on each page of a thread. I thought I had it figured out using:

<xen:if is="!{$visitor.user_id} AND {xen:number $thread.reply_count} > 2 AND !in_array({$thread.thread_id}, array(9998,9999))">
<xen:if is="{$post.position} % {$xenOptions.messagesPerPage} == {$xenOptions.messagesPerPage} - 2 OR {$post.position} == {$thread.reply_count} - 1 AND !{$message.conversation_id}">
Ad Code
</xen:if>
</xen:if>

This seems to work perfectly 99% of the time, but I'm noticing a few anomalies:

• On one 5-page thread, an extra ad is shown on page 4.
  A horizontal ad is showing correctly above the last post on pages 1-3, but then on page 4 there are two ads, one above and one below the last post. I'm not sure why page 4 is getting 2 ads. Page 5 has only one reply and shows no ad. There was a deleted post on page 1, I don't know if this has any impact. (Edit: permanently deleted the 1 deleted post in the thread instead of just removed from public view, and no change, so maybe math error because the last page has one post???)
  
  
• On one long 56-page thread, there is simply no horizontal ad shown at all. The threadID is not 9998 or 9999. I can't figure out why the above is ruling out this thread... The thread link is /threads/thread-title.629/ and 629 is not in the array (9998,9999)
  
  Edit: Correction -- it appears on this one thread, it's the {xen:number $thread.reply_count} > 2 that is not showing an ad when present, even though there are hundreds of replies to that thread ?
  
  Edit2: appears this point is solved by changing
  
  AND {xen:number $thread.reply_count} > 2
  to
  AND {$thread.reply_count} > 2
  
  For some reason the only thread that didn't seem to work with the {xen:number $thread.reply_count} > 2 conditional was the 56-page thread in question (there may be others, but I didn't find another...) Not sure if it was based on the number of pages or something about the particular thread... but changing it to {$thread.reply_count} > 2 as the conditional now works... curious...
  

Any ideas?

 

[island]

OK, better way to do it was to create a new template
ad_message_above

Include ad_message_above template above post area in template
message

Then change conditional to simply
<xen:if is="!{$visitor.user_id} AND {$thread.reply_count} > 2 AND !in_array({$thread.thread_id}, array(9998,9999))">
<xen:if is="{$post.position} % {$xenOptions.messagesPerPage} == {$xenOptions.messagesPerPage} OR {$post.position} == {$thread.reply_count} AND !{$message.conversation_id}">

 

[island]

Correction to above: parenthesis needed for consistent operation

<xen:if is="!{$visitor.user_id} AND {$thread.reply_count} > 2 AND !in_array({$thread.thread_id}, array(9998,9999))">
<xen:if is="({$post.position} % {$xenOptions.messagesPerPage} == {$xenOptions.messagesPerPage} OR {$post.position} == {$thread.reply_count}) AND !{$message.conversation_id}">