ipv4 checksum recalculation after ip change.

Hi,

RFC 1624 https://tools.ietf.org/html/rfc1624 defines a method to update the checksum after a change in the IP header. However, it is for 16 bit field changes. So if modify a 16-bit IP header field (total length, identification etc) I can follow this RFC. But what about an IP address change which is 32 bit? I need to run this update twice? once for "lower half" and "upper half" of the new ip address?

thanks.