Current SPSS user here who has trouble weighing my survey data using Tableau for basic frequencies and cross-tabs

My dataset looks like this and it has several demographic variables, question variables, and a 'WEIGHT_W93' variable. When I ran the following in SPSS to get the unweighted crosstabs

WEIGHT OFF.
	CROSSTABS 
	/TABLES= 	F_AGECAT BY	  NEWSPLAT_a_W93
	/FORMAT=AVALUE TABLES
	/STATISTICS=CHISQ
	/CELLS=COUNT ROW COLUMN TOTAL.

my output is this:

To get weighted crosstabs in SPSS, I run this:

WEIGHT BY WEIGHT_W93.
 
FREQUENCIES
 
	/VARIABLES= NEWSPLAT_a_W93
 
	/FORMAT=AVALUE TABLE.

to get the following:

In Tableau, however, there has been some slight to minor differences in the unweighted and weighted frequencies. For unweighted frequencies, what I do is to create a calculated field unweighted

sum([Qkey])/total(sum([Qkey]))

but my output looks slightly different:

For weighted crosstabs, I create this calculated field weighted using this:

sum([Weight W93])/total(sum([Weight W93]))

to generate crosstabs that look slightly different from the SPSS version:

Why is this the case? What am I doing wrong?