This report explains the methodology used to develop Version 4.4.3 of the REScheck software developed for the 1992, 1993, and 1995 editions of the MEC, and the 1998, 2000, 2003, 2006, 2007, 2009, and 2012 editions of the IECC, and the 2006 edition of the International Residential Code (IRC). Although some requirements contained in these codes have changed, the methodology used to develop the REScheck software for these editions is similar. Beginning with REScheck Version 4.4.0, support for 1992, 1993, and 1995 MEC and the 1998 IECC is no longer included, but those sections remain in this document for reference purposes.