Can anyone advise on how to set an app to launch on a partiuclar day

I need an XL spreadsheet to open on a monday morning.

I have set up a a basic app object to auto run at logon and set the
availabilty schedule to mondays between 8am and 12 noon but it launches
multiple instances every minute or so during that time.

unsurprisignly the users find this frustrating

what am I doing wrong this approach worked with Zfd 3.x but fails under ZfD