When does the processing timeframe begins?

[zidan]

My applications (I-140andI-485)were arrived at TSC in july 27 2007.This date is shown on the notice date I-797.But online it shows the folowing :In september 19 2007,we received this case...
Can some body tell me please when the processing time frame begins,since july 27 2007 or since september 19 2007 ?