A rep/tech cannot be on a payplan AND have customized commissions set at the bottom of their profile. If a payplan is chosen for a rep/tech, the option to enter customized commissions (the commission columns at the bottom of a rep/tech profile screen, and/or the 'Tech Commission' section on the right side of a tech's profile screen) disappears. 

For information on assigning payplans, see help article 'Adding/Assigning New Pay Plans (Video Explanation).'

For information on entering customized commissions for reps, see help article 'Editing Rep and Package Commission Details.' 

For information on entering customized commission for techs, see help article 'Editing Tech Commission Details (No Payplan).'