When a cube is published for the first time in Upfront the publish timestamp is attached to the cube. But when the cube is refreshed the timestamp in Upfront does not change. You can change this by executing this script with the NOTIFY option.

extra info:
model name is Great Outdoors Company.mdl
(published) cube name in PowerPlay Enterprise Server (PPES)

***************** Script *********************
echo 1. disable the cube in PPES
echo 2. build the cube
echo 3. enable the cube and trigger the notify event so that the modified cube date in Upfront is current

"c:\program files\cognos\cer4\bin\ppadmtool.exe" connect <SERVERNAME>:8010 user cognos password cognos disable "Great Outdoors Company"

"c:\program files\cognos\cer4\bin\trnsfrmr.exe" -n -s "C:\Program Files\Cognos\cer4\samples\PowerPlay\Cubes and Reports\Great Outdoors Company.mdl"

"c:\program files\cognos\cer4\bin\ppadmtool.exe" connect <SERVERNAME>:8010 user cognos password cognos enable "Great Outdoors Company" NOTIFY CUBE_OBJECT "/Great Outdoors Company" EVENT=UPDATE