SECTION 1: Chapter 41 of the General Laws is hereby amended by inserting after section 108 P the following section: - Section 108Q. In any city, town or district that accepts this section, an assistant collector or an assistant treasurer who has completed the necessary courses of study and training and has been awarded a certificate by the Massachusetts Collectors and Treasurers Association as a certified Massachusetts municipal assistant collector or a certified Massachusetts municipal assistant treasurer or a certified Massachusetts assistant district treasurer, shall receive as compensation from such city, town or district, in addition to the regular annual compensation paid by such city, town or district for services in such office, an amount equal to 5 per cent of such regular annual compensation, but not more than $500 per year. An assistant collector or assistant treasurer who has been awarded both certificates referred to above shall receive such additional compensation for only one such certificate. In order to qualify for such additional compensation, an assistant collector or assistant treasurer shall submit to the mayor or the board of selectmen of such city or town, or the governing board of a district proof of the award of either or both such certificates. The additional compensation provided in this section shall be prorated for any 12 month period in which an eligible person does not hold the office of assistant collector or assistant treasurer for 12 consecutive months. Such additional compensation shall be discontinued when certification is discontinued or withdrawn.