(1) ICAO has been trying to organize the numbering system. ICAO felt that SP A202 and SP A224 are foreign from ordinary Special Provisions so they removed these 2 SPs from the 200 series and installed a new 300 series. Without changing the last two digits, ICAO renumbered SP A202 to SP A302, and SP A224 to SP A324, respectively. As you may know, SP 800 series are SPs which IATA had installed.
(2) When the person in charge of ICAO installed SP A198, he was not aware that another individual in charge of IATA was installing SP A807 with identical contents. Thus this duplication occurred which I believe will be corrected with an addendum.
(3) SP A197 spells out that if the Environmental hazardous substance is less than 5L or 5kg, it will be treated as “Not Restricted” Addendum No. 1 to DGR 56 Edition was issued on 8 Jan. 2015 (refer to TOPICS on this home page) where it says if the shipper desires to ship non-regulated EHS as dangerous goods he may do so but he must mark the shipment according to regulations.