Try replacing the javascript code from the footer of the t_editaction.tpl with

<script type="text/javascript">
{if $auction->auction_type=="3" }
BIN_ONLY_hide_var(1);
{elseif $task!='editauction'}
    BIN_ONLY_Select(0);
{/if}
</script>

Perhaps you have this too around the initial price area in the same template:
     {else}
      <input class="inputbox" type="text" size="7" name="initial_price" id="initial_priceID" value="{$auction->initial_price}" alt="initial_price" style="display:{if $auction->BIN_price>0}block{else}none{/if}" />
      {$lists.currency}
     {/if}

You should remove
style="display:{if $auction->BIN_price>0}block{else}none{/if}"

Wait to see if this works,
Sorin

This is included in the latest 1.6.9 build.
For other users that have prior to today's build, to check this out these above are the fixes .

Sorin