I pump twice at the office with 4-5 hours apart. So, my breasts are full of milk. From my expreience, if I use electric pumps, it's easier for me to express the milk when my breasts are fuller.
Of course, pumping more frequently can stimulate more milk generation. The amount should be more in total but will be less in each pumping.
So, MrsBunBun, I suggest you to see your body's situation. You may make reference with other mothers' schedule. Some will feed and pump before going to work and just coming back home from work. They pump at the office in the afternoon.
For me, my boy does not allow me feed and pump at the same time. So, I pump during lunch time and after work. But, remember, use 2 pumps at the same time can obtain more milk.