Pivot sort by expression not working

[43918084]

I am trying to sort by expression based on Descending order of  FABS(t1 Amt HKD000 - t0 Amt HKD000 ).  However when I set the sorting by expression, it returns the below result and it is not per my requirement.

Hope I could seek some guidance on how to resolve.  Many thanks.

name	Var HKD000	t1_Amt HKD000	t0_Amt HKD000
total	(46,959,090)	17,391,567	64,350,657
ABC	(86,589)	741,570	828,159
Mary	(11,688,000)	16,649,997	28,337,997
Jona	(35,184,501)	-	35,184,501