For JA purposes, if you are employed in a wage earning capacity you sign off for days you work and can get paid for days of unemployment. For self employment, your self employment income is assessed in full without disregards. If a single person ,say, has average self employment income exceeding 204-00 euro weekly, then that person would not qualify for JA.
What intrigues me about your post however, is what is a "self employment job"? This employment is probably not self employment at all, but wage earning employment, albeit with commission type earnings. I would advise you to contact your local Social Welfare Inspector and discuss the matter with him/her before taking up this employment