js still not rounding correctly

I thought this was solved but it's not: Q_23425200.html

Here's the page:
http://www3.sympatico.ca/spowell/feecalc.html

and the updated script:
http://www3.sympatico.ca/spowell/memCalcnew.js

Entering 20952156 for example in total sales - the subtotal is $11,728.52
and gst is $586.43
which totals correctly to $12,314.95.

However - entering 410517424  - the subtotal is $44,165.12
and gst is $2,208.26
for a total of $46,373.37, which is 1 cent less.

Can someone explain what's going on here? I can't figure out the inconsistency...