Manual pump issues

Kris🐶🐶👶🏼
 Ive been using an electric double pump for 3 months and i get plenty if milk out but its such a pain and its definately not convenient to take to work etc...  It takes me like 5 minutes to get set up, and if the babies squeeling than kt takes longer to get set up and its  just all around a hassle. 
I started using my manual pump 3 days ago and it is so much more convenient especially to take to work but i dont seem to be getting as much milk out. Idk if im doing something wrong (its pretty self explanatory) does anyobe have any suggestions how to get more milk with the manual? Ive actually been pumping more times a day with the manual bc its not as much of a pain so i thought id be getting more milk out. Ive gotten about 4-5 ounces less per day. 
I thought that i read befor that many women get more milk out with the manual pump.