Utsusemi: Ichi is going to have you as the spell target, so at no point is the SpellTargetType going to be a monster (If you did utsusemi <t> as your macro, then you'd never cast utsu on yourself while fighting, so changetarget wouldn't be ideal here either I don't think).
Code
<elseif spell="Utsusemi:Ichi">
<if subjob="DNC">
<command>input /ja "Box Step" < ;t> ;</command>
<cancelspell />
</if>
<else>
<equip when="precast|midcast" Set="Utsusemi" />
</else>
</elseif>
(Note: remove the spaces before the semicolons on the box step line)
There is probably a more elegant way to do the above, using some form of changetarget and changespell. Also I didn't see the job variable in the documentation, so I just based it on subjob assuming that you would be using a different script if this was for NIN or DNC main.
so I'm guessing you just need to add
Code
<changetarget target="& lt;t& gt;" />
without the spaces after the & (not sure how to make it display without showing the < > brackets
I originally did the "& lt ; & gt ;" thing but since I was being lazy and not using the {code} bbcode, it went ahead and processed it as regular less than/greater than symbols.
2nd edit: Damnit, it still formats it.