Southwest departing OAK

[KATLPAX]

Departing OAK Sunday I noticed (I think) two Southwest flights started their take off roll not from the threshold of 29 but much farther down the runway (about at the point of that large engine runup corral, 1/4 way down?). Ive been in and out of KOAK and never myself departed except from the threshold/piano keys, either from 29 or 11. Just curious as it seemed odd at the time. Why wouldnt the crew want full use of the runway?

Just curious,

Thanks, and happy holiday all,

Cattle Pax

[Doors to Automatic]

Probably at light weight (going somewhere like LAX or LAS) and didn't need the full length - saved 5 mins taxy time.