IA vs PG: distinctly different games?

[Blackcloud6]

Unit scale is different: in PG the infantry is platoons, in IA they are companies.  Combat has nuanced differences.  Artillery is either on board direct fire field guns and indirect fire has to be planned out.  Machine Guns are handled differently too.  Although there are many similarities in the two rule-sets, which I think is a good thing as it makes the transition easy, there are enough subtle differences that gives the feel of early WWI combat in IA distinct form that of PG's WWII..