Not sure why this isn't calculating..

Three columns...

In time

Out Time

Total Time (calculate based on in and out entered)

           <field name="hours1" w="18.182mm" h="10.04mm" access="readOnly">

                  <ui>

                     <numericEdit>

                        <border presence="hidden">

                           <?templateDesigner StyleID aped0?></border>

                        <margin/>

                     </numericEdit>

                  </ui>

                  <font typeface="Myriad Pro"/>

                  <margin topInset="1mm" bottomInset="1mm" leftInset="1mm" rightInset="1mm"/>

                  <para vAlign="middle" hAlign="center"/>

                  <border>

                     <edge/>

                     <corner thickness="0.1778mm"/>

                  </border>

                  <calculate>

                     <script>if( HasValue(spec1b) &amp; HasValue(spec1a) ) then

// compute time difference in minutes

var TimeDiff = (Time2Num(spec1b.formattedValue, "h:MM A") - Time2Num(spec1a.formattedValue, "h:MM A")) / (1000 * 60)

// truncate to hours

var HourDiff = Floor(TimeDiff / 60)

// get minutes less than 60

var MinDiff = Mod(TimeDiff, 60)

// build fomatted dispaly string

Concat( Format("Z9", HourDiff), ":", Format("99",MinDiff) )

else

// if any values missing null the output

null

endif

</script>

                  </calculate>

               </field>