Inconsistent format for same tag

Hi,

I'm using FM10 + DITA-FMx1.1.13 + Window7 64bit (but I think this is not DITA-FMx problem).

I am inflicted with mysterious behaivour.

I created a simple DITA file (task)

-------------[CODE]-------------

<title>XYZ</title>

<taskbody><steps><step><cmd>STEP_1</cmd>
<choices><choice><p><uicontrol>XXX</uicontrol></p></choice>
<choice><p><uicontrol>YYY</uicontrol></p></choice></choices></step></s teps></taskbody>

--------------------------------------

And rendered result on FM10 is

XYZ

----------------------

TASK

1. STEP_1

     - XXX

     - YYY

----------------------

But... XXX and YYY is different format!! XXX is larger than YYY and different font when PDF is created.

Help!! PLEASE.

(I confirmed this phenomena on 2 machines with same environment)