This is an ACI rule set question. The rest of you go away... I derive the listings for each period on the 1004MC form. When I run Par Logic, it says the total listings on page 2 must equal the total of the three columns. This is illogical because a listing might appear in three time periods. Suddenly, I recalled that according to Henry Harrison's guide, the listings in the column are current listings sorted back over the time they were in effect. Sorting the current listings back over the three time periods makes no sense since it does not establish a trend, only the playing out of listings. The oldest are too few and likely to be priced too high accounting for these remaining on the market. However, when added together, these would represent current listings and the rule set would be correct. The Fannie Mae Video states that listings are to be those that were active in each time period. The Par Logic rule set does not appear to be correct but I am left wondering since if you follow the HH guide, it would be correct. Doug.