You can use this function: round(floor(3.2198 * 100) div 100,2)
I would suggest you can try to this by some parsing , as below:
Example : $Variable = 3.2148
Parsing function : parseDecimal(substring(toString($Variable),0,find(toString($Variable),'.')+3))
Output : 3.21
You can try to create a Rule with this parsing and re-use it multiple places.
Hope this helps!
Sunit Kumar Dubey