Search to bring back maps that have been modified in last week

Need to verify if this is the query to bring back maps that have been modified in last 7 days.

I have tried the following without any results and I know I have modified maps within the last 7 days.

Here are two different query statements I have tried passing into the performSearch method..

  • <ishquery><and><ishfield name="FISHLASTMODIFIEDON" level="lng" ishoperator="greaterthanorequal">18/10/2015</ishfield></and><ishobjectfilters><ishtypefilter>ISHMasterDoc</ishtypefilter></ishobjectfilters></ishquery

  • <ishquery><and><ishfield name="MODIFIED-ON" level="logical" ishoperator="greaterthanorequal">18/10/2015</ishfield></and><ishobjectfilters><ishtypefilter>ISHMasterDoc</ishtypefilter></ishobjectfilters></ishquery>

If I substiture ISHModule for ISHMasterDoc it does bring back topics.

Any suggestions?