Re: employees working variable hour each week

Firstly, apologies if this has been answered previously, but I don't seem to be able to find the right dialogue to find previous answers.

Our payroll has a mix of full timers and casual staff (this isn't a problem per sa).  Our casual staff have no set hours per week, their hours based on timesheets.  However, I can't enter zero 'Hours in Weekly Pay Period' for casual staff Cards.  So I put in 40 because this is our company's standard week.  However, this then puts 40 hrs automatically against 'Standard Pay' > 'Base Hourly'. Still not a problem ... yet.  I change the 40 to zero and save.  The problem begins when someone, anyone, modifies certain parts of the employee's card (not sure which parts): those 'particular' modifications then reset the Base Hourly hours back to 40, and no one has noticed because they weren't in, or modifying, 'Standard Pay'.  Now it's a problem. That employee didn't work 40 hrs, they may not have worked at all that week, but now they appear in 'Process Payroll' > 'Employee Pays' as earning 40 hrs.  So now imagine 90 employees, per week, and I don't notice that there's an extra employee in there being paid who shouldn't be. 

So my question: how do I stop MYOB automatically changing Standard Hours when someone modifies something in a Card to stop this happening?

Many thanks in advance.