Although your sales manager may not be covered by the Employment Act. the definition of "wages" in Section 2 of the Act may throw some light on your question. Below is the definition of "wages" and see whether it can be of some guidance to you and see how it can fit into your question.
"wages" means basic wages and all other payments in cash payable to an employee for work done in respect of his contract of service but does not include:
(a) the value of any house accommodation or the supply of any food, fuel, light or water or medical attendance, or of any approved amenity or approved service;
(b) any contribution paid by the employer on his own account to any pension fund, provident fund, superannuation scheme, retrenchment, termination, lay-off or retirement scheme, thrift scheme or any other fund or scheme established for the benefit or welfare of the employee;
(c ) any travelling allowance or the value of any travelling concession;
(d) any sum payable to the employee to defray special expenses entailed on him by the nature of his employment;
(e) any gratuity payable on discharge or retirement; or
(f) any annual bonus or any part of any annual bonus;