The seat elements have a location element that specifies the seat's x/y coordinates within the table image. The software does not dynamically arrange the seating, you've got to tell it where to put the seats. So, dropping seats 8 through 10 won't move seats 1 through 6.
The easiest thing to do, in my opinion, would probably be to remove seats on the "corners" (2, 4, 7, and 9), then renumber the remaining seats to be seats 1 through 6.
<table>
<image>
<path>images/RacetrackTenSeatTableLarge.gif</path>
<size width="770" height="350" />
</image>
<labels>
<font name="Tahoma" size="15" bold="true" italic="true" shadow="true" />
<text color="white" highlightColor="white" highlightBackgroundColor="blue" />
<size width="200" height="26" />
<options showSeatNumber="inuse" />
<name>
<location x="center" y="center" />
<size width="350" height="75" />
<font size="40" italic="false" />
<text color="yellow" />
</name>
<unavailable>
<text color="red" />
</unavailable>
<seat number="1">
<location x="395" y="0" />
</seat>
<seat number="2">
<text align="right" />
<location x="570" y="162" />
</seat>
<seat number="3">
<location x="395" y="324" />
</seat>
<seat number="4">
<location x="175" y="324" />
</seat>
<seat number="5">
<text align="left" />
<location x="0" y="162" />
</seat>
<seat number="6">
<location x="175" y="0" />
</seat>
</labels>
</table>
If you don't like that positioning, you'll have to play around with the x/y coordinates of the seats to get them where you want. You can modify the blueprint file while the Seating Chart screen is displayed. Pressing F4 (if you've still got F4 bound to the Seating Chart screen) will cause the screen to refresh, and changes you've made will be reflected.