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ASCE 7-98 Wind Pressure Questions

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In C6.5.5 of ASCE 7-98, it states that design for applications of serviceability, design using maximum likely events, or other applications, wind speeds associated with the mean recurrence intervals other than 50 years may be used by multiplying the design pressures by the factors in Table C6-3.  Has anyone used this clause to justify using smaller (or larger) pressures? 
Because ASCE 7 doesn't specify serviceability requirements, it is common to adjust levels of acceptability.  For deflection, L/360 may be changed to L/240, or H/500 changed to H/250...for vibration, a reduced acceleration, etc...  But, what situations would warrant a change in the Return Period?
Another question, in ASCE 7-98, the directionality factor has been separated from the load factor and is now included in the equation for velocity pressure.  Consequently, the velocity pressure is reduced by 0.85 while the new load factor is increased from 1.3 (in ASCE 7-95) to 1.6.  My question is why weren't the ASD load combinations affected?  Are the wind pressures now lower for ASD combos with 7-98 than with 7-95? 
(I understand that wind speeds were adjusted in the hurricane zones because of new data, hurricane importance factors, etc..., but what about inland areas where the 90mph wind speeds stayed the same from 7-95 to 7-98?)
David Dickey