I thought the point was that ICANN does not provide any funds to IETF and RIRs for their internal costs (such as they are) relating to IANA processes (which I assume is primarily policy-related). By contrast, ICANN funds its own costs relating to IANA policy-making, as well as funding the IANA Functions Operator aspect of IANA.
Sorry, what "IANA policy-making" are you talking about? AFAIK, the vast majority of policy making is related to various gTLD-related issues, with a bit of ccTLD policy thrown in on occasion. There is also tiny bit of numbers-related policy making. That is, the vast majority of ICANN's resources are spent on stuff that happens before IANA staff gets involved.