In MecaWind there is a checkbox option that indicates "Include ASD Load Factor of 0.6 in Pressures", which is shown in the screen shot below.
When calculating the pressures, the software will then multiple those pressures by 0.6 which is the load combination factor that is used in ASCE 7-10 and later for ASD Load Combinations:
Reference ASCE 7-10 2.4 Combining Nominal Loads using Allowable Stress Design
5. D + 0.6*W {0.6 times wind)
6a. D + 0.75*L + 0.75*(0.6*W) + 0.75*(Lr or S or R) (Again 0.6 times wind, but in this combination also times 0.75).
7. 0.6*D + 0.6*W
The main reason MecaWind has this option, is there are many users designing windows and doors that compare pressures from MecaWind to those they have from old information. Many of the old ratings are based upon ASD pressures from ASCE 7-05 and earlier (Which was based upon ASD), and so in order to compare pressures this option was added.
If you are using and applying your own load combinations, then you want to UN-CHECK this box and use the Un-factored pressures (LRFD).