I believe it should be 0x1A698 with the column scale starting at 0X1A688. It's 16bit, 1 row with 8 columns.
Wouldn't this be starting at 0x1A698 to 0x1A6A8 and a total of 2 Bytes (16 bit)?
Edit: 0x1A688 is correct. I just realized the Column scale is referring to the X-Axis.
<XDFAXIS id="x" uniqueid="0x0">
<EMBEDDEDDATA mmedtypeflags="0x02" mmedaddress="0x1A688" mmedelementsizebits="16" mmedcolcount="8" mmedmajorstridebits="16" mmedminorstridebits="0" />
<units>V</units>
<indexcount>8</indexcount>
<decimalpl>4</decimalpl>
<embedinfo type="1" />
<datatype>0</datatype>
<unittype>0</unittype>
<DALINK index="0" />
<MATH equation="0.000391 * X">
<VAR id="X" />
</MATH>
</XDFAXIS>