apportionment vs apportioning

apportionment and apportioning both are nouns.

Word	Noun	Adjective	Verb	Adverb
apportionment	Yes	No	No	No
apportioning	Yes	No	No	No

As nouns, apportionment and apportioning are synonyms defined as:

apportionment and apportioning: the act of distributing by allotting or apportioning; distribution according to a plan

Other synonyms of apportionment include allocation, allotment, assignation, parceling, parcelling.

apportionment (noun)	apportioning (noun)
the act of distributing by allotting or apportioning; distribution according to a plan	the act of distributing by allotting or apportioning; distribution according to a plan