Structured vs Explicit cell reference using index match issue

[Georgem106]

I'm using Index-Match to match Full Names with head count in that party. I have it working but it uses both the structured and explicit cell reference. I can't figure out why when I add a new row in my table, the column with the index-match formula wont populate the last row.
This is the formula used:
<code style="margin: 0px; padding: 0px; border: 0px; font-style: inherit; font-variant: inherit; font-weight: inherit; font-stretch: inherit; line-height: inherit; font-family: Consolas, Menlo, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace, sans-serif; vertical-align: baseline; box-sizing: inherit; white-space: inherit;">=IFNA(INDEX(AA:AA,MATCH([@[Preferred Seating 1st Choice]],D:D,0)),"")
</code>Column AA has the head count number and column D has the list of full names. Preferred Seating is the column used to reference the search.
I looked around and can't seem to find why it wont fill in the last row after that rown info is entered. I can only assume it has something to do with the mixed Explicit-structured cell/column references. Any help please.

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[Georgem106]

Can anybody provide any suggestions?

 

[RoryA]

Is there a reason you aren't using structured column references rather than A:A and D:D?