No, companies will expect you to have filled out their system as per their requirements. Leaving your work history blank will affect how their system analyses you. For example, it may be that they have set up to cull any candidate who has less than X years experience. By not filling out the work history component, you risk being culled even if you met the requirement.Most importantly though, the companies have given you instructions on how to apply for jobs there. By ignoring thse instructions, you risk coming across as unprofessional and believing that you do not need to follow rules that everyone else must. They don't care that you have twenty other jobs you have filled in applications for, they only care about their position.