Tax and social security contribution for entreprise Individuelle?

Could you please confirm if my calculations below for social security charges and tax are correct.

• Business set up in France: Entreprise Individuelle. Profession liberal (BNC).
• Gross annual income: 62,000 euros
• Social security contributions (travailleur hon-salarie TNS): 22,050 euros
• Private unemployment cover: 1,359 euros
• From calculez vos cotisations - no need to verify.
• Net income subject to tax: 38,591 euros
• Income tax: 4,853 euros (calculated from www3.finances.gouv.fr, using model simplifie and filling annees de naissance: 1981 and Revenus d’activite (field 1AJ): 38591)
• Net income after tax: 33,738 euros

Questions:

1. If I hire an accountant, at which point I can deduct the accountant fees, before any charges or taxes are being paid?
2. Referring to this question - what key benefits are there from CGA membership? Why profits will be increased by 25% before calculating social security charges?
3. Do you see any benefits in terms of lower social security charges or tax when operating a different type of company, for example EIRL or EURL?
4. If my gross annual income would be 67,000 euros, I can see that I would need to pay Régime Complémentaire Vieillesse Classe 5 instead Classe 4 and that would cost me extra 2,400 euros. Do you see any possible workarounds to avoid this step in pension payments, for example if there is a way of using corporate tax system and distributing payments in a way that the Régime Complémentaire Vieillesse classe would be lower?