The official watchdog of Fannie Mae’s and Freddie Mac’s regulator wants to know what’s the holdup with the GSEs’ implementation of new accounting practices to write off overdue single-family residential mortgages. Last month, the Federal Housing Finance Agency’s Office of Inspector General dispatched a “management alert” to the FHFA seeking answers as to why an advisory bulletin directing the GSEs to classify any single-family residence loan delinquent for 180 days or more as a “loss” has yet to be implemented. OIG issued the bulletin in April 2012, but the FHFA has given Fannie and Freddie until Jan. 1, 2015, to fully implement it.