Retrieve Values relating to max date

[#1]

Hi everyone, I am new to Qlik and I am stuck on what might be a very simple problem.

I am trying to make a gauge chart to display the work effiecney of some factory workers; the chart needs to look at the worker's most recent job endtime and use an equation to show the percentage.

My problem is that while I can easily get the timestamp of their last job from my table i can't seem to display the information relating to it.

The 'table' below shows some example information.

starttime          endTime     timeDifference(mins)     value1     value2

03:10:00          03:25:00               15                              8            1

03:30:00          04:00:00               30                              20          1    

04:05:00          04:30:00               25                              15          1

04:30:00          05:05:00               35                              8          1.50

05:05:00          06:30:00               85                              50          2

From my own understanding  I created the expression shown below

=if(GetSelectedCount(Worker) = 1,

  Ceil(    (    (MAX(Value1)/ Max(Value2)) / if( Num#(Interval(Max(time(timeDifference),'hh:mm:ss'),'mm')) = 0, Num(Num#(Interval(Max(time(timeDifference),'hh:mm:ss'),'ss'))/60,'##.00'), Num#(Interval(Max(time(timeDifference),'hh:mm:ss'),'mm'))    )    ) * 100    )

, '0')

This finds me the largest values from my table rather than those related to the latest which isn't right.

Your help with this is greatly appreciated, hopefully I explained it well enough.