STAAD calculation of Cs (IBC 7-10 seismic)

Hi all,

For the life of me, I can't figure out what I am doing wrong with my hand calculation to match up with the STAAD calculation of Cs. Currently I have the following variable in STAAD

Zip Code 90012

TL= 8

Importance Factor = 1.25

Response Modification Factor = 3.5

Site Class 4

with the rest of the variable blank.  The Cs value is 0.610 in the output file. 

Using equation 12.8-2 my hand calc Cs is 0.19. Using Sds = 0.531.

I believe it has to due with the transition period varible. Which section/step am I missing? As derviing the Sds did not require using the TL variable. 

Thank you